Soft Report - Dipartimento di Fisica - Sapienza

Istituto Nazionale per la Fisica della MateriaConsiglio Nazionale delle RicercheResearch and Develpment Center onComplex Dynamics in Structured SystemsActivity ReportJune 2004- December 20063 SOFT Scientific Report 2004-06

ContentsCover Image: Selected frames from a movie displaying eight optically trapped silicabeads (2 microns diameter) in water, morphing through the four letters S-O-F-T. Opticalmanipulation of the beads is obtained via a holographic tweezer (see the experimentalfacilities section for details): the wavefront of a laser beam is dynamically shaped by aSpatial Light Modulator and focused on the sample volume by a microscope objective.(by Roberto Di Leonardo)SOFT Scientific Report 2004-064

ContentsIntroduction 7Scientific Mission 9Management, Personnel, Participants 14Experimental and Computational Facilities 17Activity at Large Scale Facilities 31Development of the neutron Brillouin Spectrometer BRISPDevelopment of the neutron backscattering spectrometer IN13AXES: Advanced X-ray Emission SpectroscopyID16: Inelastic X-ray ScatteringExperimentsScientific Reports 48Non-equilibrium dynamics and complexitySelf assembly, clustering, structural arrestElastic and inelastic scattering of neutrons and X-raysProjects and Collaborations 109Dissemination 115PublicationsContributions to ConferencesOrganization of SchoolsOrganization of Workshop and ConferencesSoft annual workshopsSoft Web SiteAwardsContacts5SOFT Scientific Report 2004-06

IntroductionSOFT Scientific Report 2004-066

IntroductionSOFT is a CRS (Centro di Ricerca e Sviluppo) of INFM (now INFM-CNR) devoted tothe investigation of complex dynamics in structured systems.The aim of the research centre is the investigation of the dynamics in SoftCondensed Matter systems, i.e. those materials which are easily deformable byexternal fields (mechanical, electric, magnetic, ...). These materials typicallypossess structures which are larger than atomic or molecular scales; the structure(and often the supra-molecular structure), together with the dynamics at themesoscopic scales, determines unusual macroscopic physical properties. Softmaterials are of basic importance in material science because, once the relationsbetween structural and dynamical properties are known, their macroscopicproperties can be tailored. We study both synthetic and self-assembled (includingbiological) materials, as well as other physical systems in which the interactionamong the components gives rise to an emergent complex dynamics.Founded in June 2004 by INFM (Istituto Nazionale per la Fisica della Materia), andnow part of CNR (Consiglio Nazionale delle Ricerche), SOFT headquarters are at theDepartment of Physics of the University of Rome “La Sapienza”, but many otherlaboratories are based in different Universities (Camerino, Firenze, L’Aquila, Parma,Perugia, Pisa and Trento) and an important part of the activities takes place at theOperative Group in Grenoble (OGG).The first two years of operation of SOFT have resulted in an impressivedevelopment of activities. SOFT is a very lively environment: different new researchgroups joined, excellent young researchers and students from the Laurea and PhDcourses in Physics have been actracted, the laboratories have been significativelyimproved, and important scientific results have been achieved. An overview of thescientific results can be found in the “Scientific Reports” section of this booklet; thelist of publications is also included.The setting up of SOFT was made possible thanks to INFM and to the Departmentof Physics of the University of Rome “La Sapienza”, which hosts part of the CRS.The development of SOFT has benefited by internal (INFM) and external fundingfrom different international and national agencies, including the EuropeanCommission and the Italian Ministry for Research.This report summarizes the activities of the CRS SOFT in the first two and an halfyears of life (June 2004-December 2006), and offers a picture of SOFT as it is now(December 2006).Roma, December 2006Giancarlo Ruocco7 SOFT Scientific Report 2004-06

MissionSOFT Scientific Report 2004-068

Scientific MissionThe scientific works of Soft can be roughly classified in three main Activities that –in the CNR funding scheme- coincide with the three “commesse” in which theresearch center is partitioned. These activities are:A. Non equilibrium dynamics and ComplexityB. Self Assembly, Clustering, Structural ArrestC. Elastic and inelastic X-ray and neutron scatteringThe specific scientific mission of each activity is outlined below.A. Non equilibrium dynamics and ComplexityOne of the characteristic of the CRS SOFT is the long standing expertise of many ofthe senior investigator in the field of undercooled liquids and the glass transition.Taking advantage of this expertise, we are transferring the culture, the tools andthe language pertaining to this fields in the Soft Matter physics. In the undercooledliquids field there are, however, specific sectors that are currently under very quickdevelopment. We think that the deeper investigation of these aspects of the physicsof supercooled liquids, is of fundamental importance for the transfer of knowledgetowards (and backwards) the Soft Matter research. The aim of this activity is tofollow the state of the art research in those sub-fields of the physics of liquids thatare more close to the Soft Matter physics. For this reason we are studying materialswhich are not usually classified as Soft Matter. The specific actions, describedbelow, refer to the study of the interplay between different time-scales in thesystem dynamics. These different time-scales can be either induced by externalflows -as in Research Project A1- or generated by the aging phenomena -as in A2-.The systems that we are investigating include molecular liquids, polymers andcolloids.A1. Slow dynamics of systems in steady states induced by external flows.The aim of this Proget is the study of the dynamics of liquids, polymers and colloidskept off-equilibrium (more specifically: in a steady state) by external forces. Inparticular our goal is the test of the theoretical predictions based on the extensionof the Mode Coupling Theory (MCT) on the shape of the correlation functions [1],and the test of the validity of a generalized form of the dissipation-fluctuation (FD)relation for systems in stationary states [2]. It is also our aim to verify thegenerality of these predictions by investigate a) different kind of systems (rangingfrom molecular glass formers to colloids), b) different kind of observables, and c)different kind of flows. As example of external flows, one can easy think to studysystem under shear (with different time dependence of the shear rate, eitherperiodic or stationary) or system subjected to temperature gradient. Other lesscommon external forces can be also envisaged as, for example, the case of systemsunder composition gradient, or subject to intense electric field as those produced bypulsed Lasers. After the system under investigation has been put in a stationary9SOFT Scientific Report 2004-06

Missionstate, we aim to measure the correlation function C(t) of a certain observable A(t)and measure the response function R(t) of the system after a perturbation(conjugate to A(t) in the system Hamiltonian) is applied. The study of C(t) wouldallow to verify the MCT prediction, while the comparison of C(t) and R(t) will giveinformation on the generalization of the FD relation. Among the possibleobservable, we plan to study (at least) a scalar observable (number density), avector one (dipolar polarization) and a pure rank two tensor one (the polarizabilityanisotropy).A2. Generalized fluctuation-dissipation relation in aging systems.The aim of this Proget is the study of the off-equilibrium dynamics in supercooledliquids, polymers and colloids. In particular our goal is the experimental test of welldefined theoretical predictions: the existence of scaling laws for the physicalobservable in the aging regime, the existence of a relation between the responseand the (conjugate) correlation functions and, consequently, the measurement ofan effective temperature [2]. Moreover, it is our aim to verify (as much as possible)the universality of these prediction by investigate different kind of systems (rangingfrom molecular glass formers to colloids) and different kind of observable. Amongthe latter, and according to our experimental capabilities, we selected a scalarobservable (number density), a vector one (dipolar polarization) and a pure ranktwo tensor one (the polarizability anisotropy). To reach our goal one needs to 1)bring the selected sample out of equilibrium 2) measure the correlation functionC(t1,t2) of a certain observable A(t), as a function of both times and 3) measurethe response function R(t2) of the system after a perturbation (conjugate to A(t) inthe system Hamiltonian) is applied at time t1. Steps 2) and 3) alone can be used tostudy the scaling laws expected for correlation and response functions respectively,while their comparison (or better the simultaneous measure of 2 and 3) bringsinformation on the generalized Fluctuation-Dissipation Theorem (FDT) and on theeffective temperature. The steps 1-3 should be repeated for the three differentobservable listed above: a) density, b) dipolar polarization and c) polarizabilityanisotropy (and, of course, for different samples).[1] C. B. Holmes, M. Fuchs, M. E. Cates, cond-mat/0210321[2] L. F. Cugliandolo, cond-mat/0210312B. Self Assembly, Clustering, Structural ArrestWithin soft-matter research, the CRS SOFT privileges studies on self-assembly,clustering and structural arrest on colloidal systems, including biological mattersystems. Studies are focused on the three relevant levels of comprehensionrequested when dealing with colloidal systems: the microscopic level (chemicalphysics of the basic interactions), the mesoscopic level (search for effectivepotentials between colloidal particles tracing out the solvent, predictions of thestructure and dynamics) and the macroscopic level (structural and dynamicalproperties of the compounds, equilibrium and non-ergodic properties). Theactivities are organized around complementary research projects.SOFT Scientific Report 2004-0610

Missioncolloids and soft colloidal systems, selecting the model systems among the mostprominent candidates for grasping the essential features of dynamic arrest.Emphasis is on the possibility of performing a detailed comparison betweenexperimental data and theoretical predictions based also on the mode couplingtheory of the glass transition. We focus on understanding the system's kineticarrest phase diagram, i.e. the regions in phase space where disordered arrestedstates can be expected, both gels and glasses. We examine when and how thesestates are kinetically stabilized with respect to the ordered lowest free energyphases, in order to provide a framework for interpreting and developing new ideasin the study of new materials. Finally, we study chemical gels to investigate theunderlaying universal properties of gelation and glass formation.C. Elastic and inelastic X-ray and neutron scatteringSoft matter, including glasses, polymers and biological matter, though beingmacroscopically isotropic, has different properties due to its microscopic structureand dynamics. Specific and universal trends are observed at the same time and arelationship with the microscopic and mesoscopic behaviour is expected. Most ofthe activity is performed at the beam lines in Grenoble where both the scientificactivity and the technical advances in neutron and x-ray scattering represent arelevant enterprise. A close cooperation of the group in Grenoble and variousgroups in Italy is a relevant added value which makes this activity interdisciplinary.Activities are organized around complementary research projects.C1. Technical developmentsFour beam lines represent the major technical effort. These beam lines are installedat the neutron and photon sources ILL and ESRF located in Grenoble (France) andare almost unique facilities in the world.The two neutron beam lines are IN13 and BRISP. The first one is a backscatteringthermal neutron spectrometer useful for quasi-elastic investigations in the µeVrange up to 5 Å -1 momentum transfer. This performance make this instrumentextremely important in the study of relatively slow (5-100 ps) relaxation processesin disordered systems like glasses and biological molecules. The instrument hasbeen almost rebuilt in the last years thus improving its performances in terms ofmomentum-energy range and in terms of intensity (see detailed description). Thesecond instrument, BRISP, has been completed in 2005 essentially on timeschedule and during the two reactor cycles of 2006 has been commissioned. Thisinstrument is devoted to the study of dynamics of disordered systems with specialconcern for the collective dynamics with sound velocity ranging from 500 m/sto4000 m/s (see detailed description). This is a unique machine and its constructionimplied a big effort in terms of technical developments because it employs newsolutions, never developed before.The two photon instruments are ID16 and AXES. The first one initiated the study ofcollective dynamics employing ultra-high resolution x-ray scattering, thusintroducing the companion technique of neutron scattering. ID16 is the x-raycounterpart of BRISP and the two instruments perform complementary and parallelSOFT Scientific Report 2004-0612

works having a strong overlap in terms of energy resolution and momentum-energyspace, while neutron and x-ray photon interact in a different way with matter. AXESis an soft x-ray instrument which can perform dichroism study of complex surfaces.In addition to the effort in maintaining and developing the instruments, thetechnical activity is also devoted to the sample environment in order to performexperiment in a wide temperature and pressure range using either photons orneutrons.C2. Dynamics in disordered materialsA large scientific effort is devoted to the experimental study of the dynamics ofdisordered materials, either liquid or glasses. The activity is developed along twomajor lines.First, the dynamics of liquid metals is investigated using neutron and x-rayscattering. The aim of these investigations is the identification of universal trends inthe collective mode velocity and damping. The role of the almost free electrons isconsidered as the most important information which can be gained and can be usedto compare experimental results to the modern electron gas theories.Second, the investigation of the fast dynamics of glasses, including the special classof borated glasses, and hydrogen bonded materials is investigated, again usingneutron and x-ray scattering, in order to identify the relevant parameters whichgive rise to the propagation of collective dynamics and those establishing the selfdynamics.C3. Dynamics in biological matterThe biological matter represents a special case of soft matter where typicalcharacteristics of liquids and glasses coexist at the same time. Indeed, in biologicalmatter a large hierarchy of relaxation times plays a basic role and the functionalityof biomolecules is strongly related to the dynamics in a way which is not yetdefined. The fast and slow self-dynamics of biomolecules can be studied by meansof incoherent neutron scattering thanks to the very high incoherent cross section ofhydrogen, in atom copiously present in biological matter. In addition, the possibilityof substituting hydrogen with deuterium, the collective dynamics of hydrationwater, for instance, can be also studied. The effect of hydration water on thevarious proteins is a major concern and several investigations are introducing newviews on the behaviour of these systems.13SOFT Scientific Report 2004-06

PersonnelManagement, Personnel and ParticipantsDirectorGiancarlo RuoccoAssociate directorFrancesco SciortinoExecutive CommitteeLuigi CristofoliniDaniele FiorettoGiancarlo RuoccoFrancesco SacchettiFrancesco SciortinoRenato TorreAdministrative StaffPaola Angelici 1Angelo Campus 1Giovanna Loffredo 1Giulia MarinelliTechnical and Scientific SupportSimone AisaSara ErriuAlessio LaloniLaura LarotondaThe list below includes all researchers and scientists who are members of SOFT and haveparticipated to its activities in the first two and an half years of life.PersonnelThe list includes researchers and technologists hired by INFM and who are (currently 27) orhave been (three, indicated by *) members of SOFT.Roberta AngeliniGiacomo BaldiTatiana BerzinaBeatrice BonanniLivia Eleonora Bove*Simone CapaccioliLucia CapognaSilvia CaponiSilvia CapuaniLucia ComezAlessandro CunsoloAlessio De FrancescoRoberto Di LeonardoRoberto EramoVictor Erokhin *Ferdinando FormisanoFederico GorelliEleonora GuariniGianluca GubbiottiEmilia La NaveSimone MelchionnaClaudia MondelliFrancesca NataliAndrea Orecchini *Alessandro PecchiaAntonino PietropaoloDaniela RussoBarbara RuzickaTullio ScopignoEmanuela Zaccarelli1 Shared with the CRS SMCSOFT Scientific Report 2004-0614

Academic ParticipantsThe list includes researchers and professors who belong to Universities or other researchinstitutions and conduct most of their research and projects within SOFT.Marco BalucaniFabrizio BarocchiPaolo BartoliniPaola BenassiMaria Grazia BettiAdalberto BonincontroFederico BordiLucio BraicovichGiuseppe BrigantiCesare BucciCesare CamettiEnzo CampaniCinzia CasieriGiovanni CiccottiClaudio ContiLuigi CristofoliniBruno CrosignaniClaudia DalleraPaola D’AngeloFrancesco De LucaEugenio Del ReRoberto De RenziAntonio DeriuValeria Di CastroAndrea Di CiccoPaolo Di PortoAldo FerrariAdriano FilipponiDaniele FiorettoMarco FontanaAldo FontanaLeone FronzoniLuciano GalantiniCecilia GambiGiampaolo GoriniRoberto GunnellaCamillo La MesaDino LeporiniRoberto LiviVincenzo LombardiMaria Antonietta Macri'Bruno MaravigliaMaurizio MontagnaSilvia MoranteMichele NardoneGiuseppe OnoriAlessandro PaciaroniGaio ParadossiNicolae Viorel PavelCaterina PetrilloGabriella PiazzesiCarlo PierleoniGianluca RagoMarilena RicciGianfranco RisuleoAlessandro RuoccoGiancarlo RuoccoFrancesco SacchettiMarco ScampoliMario SantoroAldo SantucciFrancesco SciortinoFrancesco SetteAlberto TagliaferriRenato TorreStefano TrilloPaolo VerrocchioGabriele VilianiPostDocsThe list includes young researchers hired by SOFT or by the related Univerisities whoconduct most of their research and projects within SOFT.Marcella AlesianiSiro BuzzettiPaolo CamoraniFrancesco CasininiStefania CinelliSilvia CorezziCristiano De MicheleDavide D'emilianoSimone De PanfilisFabrizio FasanoFederico GioveAndrea GiugniJulio LargoLuca LariniStefania MarchettiIlaria PirazzoliMarie PlazanetPaola PorcariDaniele PrevostoMauro RebuzziSimona SennatoAndrea TaschinGiovanni VenturiPhD StudentsThe list includes PhD students who have been working at their thesis at SOFT in the firsttwo years of activity.Masoud AmirkhaniPatrizia AndreozziChiara BaldacchiniElisabetta BrunelloStefano CazzatoElena CornicchiRiccardo CuciniNeda GhofranihaTommaso GiliValentina GiordanoFrancesca IanniMatteo MarconiLaura OrsingherEmanuele PontecorvoCristina RossiBarbara RossiPaolo Sebastiano ScaliaFilippo ScarponiSoheil SharifiGiavanna Giulia SimeoniCamilla TerenziFrancesco ZamponiCarolina ZiparoLaura Zulian15SOFT Scientific Report 2004-06

FacilitiesSOFT Scientific Report 2004-0616

Experimental and Computational FacilitiesHere following is a survey of the experimental and computational facilities of the differentItalian laboratories of SOFT. The activities at OGG (Grenoble, F) will be presented in thenext section.• X-ray Diffraction Laboratory - UdR Camerino• Optical Laboratory - UdR Firenze/LENS• UV Light Scattering Laboratory - UdR L’Aquila• Thin Film Laboratory - UdR Parma• Spectroscopy Laboratory - UdR Perugia• Dielectric Spectroscopy Laboratory - UdR Pisa• Brillouin Light Scattering Laboratory – UdR Roma• Time Resolved Spectroscopy Laboratory – UdR Roma• Photo-Correlation Laboratories – UdR Roma• Optical Tweezing Laboratory – UdR Roma• Non Linear Optics Laboratory – UdR Roma• Static Light Scattering Laboratory – UdR Roma• Calorimetry and Rheology Laboratory – UdR Roma• NMR Laboratory – UdR Roma• Spectroscopy Laboratory - UdR Trento17SOFT Scientific Report 2004-06

FacilitiesX-ray Diffraction Laboratory - UdR CamerinoX-ray diffraction set-upThree different equipments, relevant to the activity of the center anddeveloped in recent times are: an angular dispersive x-ray diffractionset-up for measurements at high temperature conditions (up to2300K) and room pressure; a high pressure (up to 10 Gpa) and hightemperature (up to 1500 K) energy dispersive x-ray diffraction set-upand a high pressure (up to 100 Gpa) angular x-ray diffraction set-upallowing measurements at moderate temperature (up to 700 K).The x-ray source for the first two equipments is the same and consistsof a powerful Mo rotating anode (18 KW) delivering two independentbeams (one for each set-up). In the angular dispersive the beam ismonochromatic using the (002) Bragg peak of pyrolytic graphite at anenergy of 17.47 keV. This set-up is particularly useful to study andidentify phase transition and for accurate measurements of thermalexpansion in a very wide class of materials. In particular we haveespecially metals and semiconductors like Pd, Fe, Zn, Si and Ge. As anexample we report in the picture the behaviour of the (002) peak ofAg as function of temperature in the 293-1215 K temperature range.It is possible to see clearly the shift of the (002) peak for increasingtemperature as a consequence of the variation of the thermalexpansion, while the two graphite peaks (100) and (101) remain quiteat the same angular value. The red line has been recorded at 1250 Kand show the melting of Ag.The high pressure and high temperature energy dispersive x-raydiffraction set-up is realized using the second white x-ray beamcoming out from the 18 KW anode. The diffractometer includes anenergy-sensitive Ge detector with precise collimation system (sollerslits) and motorization for confining the scattering region in thevolume sample. The detection system is an LEGe detector withenergy resolution of 195 eV at 5.9 keV. The scattering angle can betuned continuously. The sample can be confined in a large volumeParis-Edimburgh high pressure cell, the only presently available inItaly and suitable for measurements up to pressures andtemperatures of 10 Gpa and 1500 K respectively. The press installedon motorized stages is shown in the picture. Successful experimentshave been performed on Ag, Ge and Polyethylene samples. We reportin the figure a spectrum of a Ge high-pressure sample under ambientconditions. This set-up allows accurate investigation of structure andphase transition in materials under extreme condition (high pressure /high temperature).The high-pressure angular x-ray diffraction set-up consist in amodified 4-circle geometry Diffractometer (KUMA-Oxford) combinedwith a miniaturized Diamond Anvil Cell (D'Anvils Ltd.) allowing thestudy of the structure and phase transitions of condensed matter in aa wide high pressure range (up to 100 Gpa) and moderatetemperature (up to 700K). The Kuma-Oxford diffractometer isequipped with a 3KW Mo anode (17.49 keV wavelength). In the nextfigure we show the special holder developed for the DAC that allowsmicrometric positioning of the centre of the cell. Besides the KUMA-Oxford detection systems that permits to collect standard scans, wehave developed a very efficient low-cost solution using an in-housemade detector holder with an high resolution x-ray photographic film(Structurix D7 Agfa). In this way we collect the entire Debye-Scherrerrings increasing statistic. The DAC used has an aperture angle of 40degrees, from -20 to 20 degs but tilting the cell respect to the x-raybeam we can obtain -10 to 30 degs. In the following picture we showthe typical Debye-Scherrer rings of Si powders at a pressure of 1.1Gpa and room temperature. Bragg spots of diamonds and spuriousring of inconel gasket are also visible. The integration of the 2-D data(fit2D software) produces one-dimensial plot and this is shown in thenext figure where it is possible to identify clearly the (111), (200) and(311) Si peaks.[1] A. Di Cicco, R. Gunnella, R. Marassi, M. Minicucci, R. Natali, G.Pratesi, E. Principi, S. Stizza, J. Non-Cryst. Sol. 352 4155 (2006).[2] http://gnxas.unicam.it, website of the Camerino research group.SOFT Scientific Report 2004-0618

Optical Laboratory - UdR Firenze/LENSLaser facility for femto and pico-second time-resolvednon-linear spectroscopy. Raman scattering, Infraredabsorption. High pressure (Diamond Anvil Cells andcorrelated equipment). X ray diffraction. Frequencyresolvedlight scattering (Sopra monochromator) anddynamic light scattering. New dielectric spectroscopictechnique, in the range 30 MHz – 3 GHz, characterized byabsolute measurements.Laser system at LENS facilityUV Light Scattering Laboratory - UdR L’AquilaHIRESUV: A High Resolution, high contrast spectrometerfor UV Brillouin SpectroscopyHIRESUV is a multiple grating spectrometer designed for highresolutionand high-contrast scattering spectroscopy in theultraviolet as well as il the visible spectral regions. Theinstrument has been set up in the Physics Department of L’Aquilaand is now available for measurement at different scatteringangles with both visible and ultraviolet radiation. The obtainedperformancies are an intrumental resolution better than 1 GHzand a contrast of about 3x10 -12 both in the visible and in the UVrange. For further details see P. Benassi et al., Review ofScientific Instruments 76, 13904 (2005).The echelle gratings used have a ruled area ofabout 200x400 mm 2 with 31.6 grooves/mm andare blazed for an incidence angle of about 75 o .Experiments performed with HIRESUV up to now essentiallyconcern with:i) UV and visible Brillouin spectroscopy of glass formingliquids in the study of relaxation processes and transversedynamicsL TT Lii) UV and visible spectroscopy of glasses in the study ofdisorder induced high frequency attenuation.19SOFT Scientific Report 2004-06

FacilitiesThin Film Laboratory - UdR ParmaDouble Langmuir Blodgett Instrument model KSV 5000: acomputer controlled and programmable Langmuir-Blodgettinstrument for the study of monolayers at the air-water interfaceas well as for the automated Langmuir film experiments anddeposition of normal or alternating multilayers onto solidsubstrates. The LB Instrument is equipped with a set of speciallydesigned and home-made troughs e.g. for limited amount ofcompounds, such as proteins or lipids, Langmuir Schaeferdeposition with proper sectioning of the area of every filmtransfer, thermal control of the subphase.Optical near field scanning microscope, produced by APEresearch and modified to perform polarization analysis, alsoin polarization modulation for optical axis determination e.g.in liquid crystalline media. Three signals can be acquiredsimultaneously (e.g. scattered, and 2 polarizations oftransmitted light) by a multiplexing system developed adhoc. It can be operated with different wavelengths. Suitablefor measuring in pump-probe configuration. The microscopecan be coupled to a LN2 cooled CCD spectrometer (JY TRIAX320), for fluorescence measurements. A suitable softwarehas been developed to perform optical nano-lithography.Null-ellipsometer with very high angular resolution (

Spectroscopy Laboratory - UdR PerugiaCryostatLASERTandem Fabry-Perot interferometer Theexciting source is a Coherent-Innova 300 modelargon ion laser operating with a typical power of300-500 mW on a single mode of the λ 0=514.5 nmline. The light scattered by the sample is analyzedby means of a Sandercock-type (3+3)-pass tandemFabry-Perot interferometer, which supplies the bestcombination of high resolution and goodthroughput, whit a finesse of about 100 and acontrast >10 10 . By varying the mirror spacing(d=0.05mm, 20mm), it is possible to collect spectracovering the 0.1-300 GHz frequency range selectingdifferent polarization geometries. The frequencyresolution of this apparatus is about 100 MHz, andthe maximum exchanged wave-vector achievable isabout 0.04 nm -1 .Control anddata aquisitionDielectric spectroscopy setup Dielectric spectrometer based on aNovocontrol Alpha S setup operating in the frequency rangebetween 0.01 and 107Hz and on HP8720C and HP8753A networkanalysers in the range 107–2·1010Hz.Photon Correlation Setup. The light source is a diode pumpedsingle mode (the λ 0=532 nm) solid state laser (Coherent)operating with a typical power of 400 mW. The setup is usuallyused in 90° scattering geometry and the light scattered by thesample, after polarization, is collected by a photomutiplier tubeand analysed by a Brookhaven BI-9000 AT correlator, a digitalsignal processor which can be used with low, mid and high speedselections of the channels (max number channels:466), withdifferent sampling time ranges, allowing to make measurementsfrom 25 ns to 1310 s. For measurements as a function of theangle, the apparatus with sample holder can be also equippedwith a 200mm turntable mounted on a circular base, withmanual or motor driven selection of angles 0.01° steps.Dielectric Spectroscopy Laboratory - UdR PisaHigh-Pressure apparatus for electric measurements. In the centralpart of the picture we can see the Berillium-Copper pressure room in whichthe sample can be inserted. Specially designed feed-throughs (top of thecell) connect the sample with the High Resolution Dielectric Analyzer fromNovocontrol, which is used for electric measurements. A thermostaticjacket is wrapped around the pressure room, enabling the control oftemperature by means of a circulators from Huber (Unistat 380w).Pressure variations, produced by a manual pump, are transmitted to thesample through a fluid. The apparatus can be used for electricmeasurements of liquid and solid samples in the frequency range 10 -5 -10 7Hz, over the temperature interval from 353 K to 193 K, and in the pressureinterval from 0.1 MPa to 700 MPa. The resolution of the electricmeasurements expressed in terms of loss factor tanδ is better than 10 -3 inthe whole frequency range (UdR Pisa)21SOFT Scientific Report 2004-06

FacilitiesBrillouin Light Scattering Laboratory – UdR RomaCCD based Brillouin spectrometer DMDP2000. In this set up the incoming laser beam, 500 mW at 5514.5nm, from a Coherent INNOVA Ar-ion laser operating in single mode owing to an intracavity ethalon and inpower stabilized mode, is focused onto the sample. The polarization of the incident beam can be either verticalor horizontal with respect to the scattering plane. The light, scattered at an average angle of 90° or 180°, iscollected by a field lens (20 cm focal length, 4 cm diameter). After selecting the polarization by a polaroid film,the scattered light is focused on the entrance slit of the SOPRA DMDP2000 mono-chromator. The latter iscomposed of a couple of two meter focal length grating mono chromators, in Fastie–Ebert mounting, each onewith entrance and exit slits and coupled in additive dispersion by an external 1:1 telescope. Themonochromator can opearte in the single pass/double monochromator or double pass/double monochromatorconfigurations at the 11th diffraction order, corresponding to a transmissions of 25% (4%) and a totaldispersing power on the exit slit plane equal to 1 cm-1/mm (0.5 cm-1/mm). In a conventional experiment allthe slits are closed according to the desired resolution width, a photomultiplier is placed in front of the exit slit,and frequency scans of scattered light are obtained by simultaneous rotation of the two gratings. In a CCDbased operating mode the two intermediate slits and the exit slit of the monochromator are fully open and theimage formed in the final plane slit is focused via of a singleachromat doublet (focal length 75 mm, magnification 1:10) onthe surface of a CCD camera. The camera is a HiResIII camera(DTA, Pisa, Italy) mounting a SITe 11003330 pixel (totaldimension 2 mm x 0.6 mm) back-illuminated CCD sensor(quantum efficiency of 80%) cooled via a Peltier element and afluid close circuit system based on an HAAKE 75 refrigerator. Inthis setup, the spectral range covered by the CCD sensor is 2cm-1, i.e., 0.002 cm-1/pixel, that correspond to ten points oneach spectral resolution as dictated by the width of themonochromator entrance slit. The image of the camera istransferred to a PC, where the BLS spectrum is obtained byintegrating the image in vertical (nondispersing) dimension.Figure: Three-dimensional image of the intensity measured bythe CCD detector (exposure time 10 s) on a sample of toluene.Time Resolved Spectroscopy Laboratory – UdR RomaImpulsive Stimulated Scattering (ISTS). Twointerfering pulsed laser beams interfere in the samplevolume stimulating a density grating whose time evolutionis probed by monitoring the intensity of a reflected cwprobe beam. Transient grating dynamics providesinformations on the non-equilibrium thermodynamics andrelaxation processes in complex fluids. Our setup consistsof an infrared mode-locked pulsed laser (100 ps pulses of1064 nm wavelength with a 10 Hz repetition rate) actingas the pump and diode-pumped intracavity-doubled Nd-YVO (CW 532 nm) providing the probe beam. A dichroicmirror is used to sent colinearly both the excitation andthe probing beams on a phase grating. The diffractedbeams are collected and refocused on the sample by twoachromatic doublets. One of the two probe beams isattenuated and adjusted in phase to serve as a referencelocal field for heterodyne detection. The reflected portionof the other probe beam is mixed with the local field on theactive area of an ultrafast amplified photodiode whosevoltage output is recorded by a 4 GHz oscilloscope. Therelaxation of a sinusoidal density fluctuation can be somonitored on a nanoscond to millisecond time windowgiving access to a broad range of relaxation phenomena(acoustic waves, structural relaxation in supercooled fluids,thermal diffusion).SOFT Scientific Report 2004-0622

Photo-Correlation Laboratories – UdR RomaConventional Photon Correlation Spectroscopyset-up (PCS). A He-Ne laser (λ=632.8 nm) of 10mW is focused on the centre of a vat mounted on agoniometer. The temperature of the sample, sit inthe centre of the vat, is controlled by a cooler-heater(HAAKE K35). The scattered light is focused,selected by a pinhole and revealed by a multimodefiber and a photomultiplier detector. A commercialALV-5000 logarithmic correlator computes theautocorrelation functions. Measurements can beperformed at various scattering vectors q (movingthe collecting arm and so varying the collectingangle) and in a correlation time window between 1µs and 10 s.Advanced photon correlation spectroscopyset-up. A He-Ne laser (λ=632.8 nm) of 35 mW issent on a polarizing maintaining single mode fiberand is focused on the centre of a vat mounted on agoniometer. The temperature of the sample, sit inthe centre of the vat, is controlled by a coolerheater(HAAKE FUZZYSTARC35). The scattered lightis collected by a single mode fiber. The photocountsare analysed by an home made software thatprovides a logarithmic correlation of the data. Formore details see the article "Software Toolkit for theStatistical Analysis of Photocounts". By means ofthe use of single mode fiber the coherence factor βreaches the ideal value of 1 and thereforeautocorrelation functions with a very high signal tonoise ratio are obtained. Measurements at variousscattering vector q (varying the collecting angle)and in a time correlation window between 1 µs and2 s can be measured.Infra Red Photon Correlation Spectroscopy (IR-PCS) set-up formeasurement of time correlation functions in non transparent/opalescentsystems. An IR (λ = 1064 nm) diode-pumped lasers is focused (lens L1in the picture) on the sample. The scattered signal can be collected atdifferent scattering angles - thus allowing to vary the momentumtransfer- through an appropriate slab-shaped window. A lens-collimatorsystem, couples the scattered intensity with an optical fiber connected toa silicon avalanche photodiode detector with 2% quantum efficiency and50c/s dark counts. The number of photon counts in a given time is thenrecorded and time-autocorrelation function is computed by a specificallydeveloped software. Several time decades are accessible with thistechnique, from few µs to 100s, while accessible exchanged momentarange from 10 4 to 10 5 cm -1 . The sample-holder cell is equipped with anheater and a temperature control device and is capable of reaching up to800K with an accuracy better than 0.1K, an essential feature for theinvestigation of cooperative and diffusive dynamics of supercooledliquids and glassy systems, as well as of macromolecular and latexnanospheres solutions.23SOFT Scientific Report 2004-06

Facilitieslaserf 2BSf 1FOBSSoftware Toolkit for the Statistical Analysis ofPhotocounts. Photon Correlation Spectroscopy(PCS) has proved to be a major technique to probedynamics in soft materials. Many variationsappeared in the course of the last decades extendingthe range of applications of PCS to: stronglyscattering media (Diffusing Wave Spectroscopy),turbid samples (multi-color and 3D PCS), infra-redand X-ray PCS. However, the core of any of theabove mentioned PCS based experiments remains adigital auto correlator: a device which is able tocompute the autocorrelation function of a timeseries of digital pulses (photocounts). Modernpersonal computers provide far enoughcomputational speed to perform softwareautocorrelation in real time, a task that oncerequired specially designed hardware. We developeda set of software classes (implemented as extensionmodules of the object oriented language Python)designed to perform basic tasks for the statisticalanalysis of digital pulse trains. Photocounts areacquired through a general purpose, counter/timerPCI board. A software approach, having access tothe full photocounts train, allows to efficientlyprototype different analysis protocols, going farbeyond the simple autocorrelation function. Ourphoton statistics toolkit, named PhotonLab, iscurrently used, within the Soft laboratories, toperform: multi-tau PCS, heterodyne Dopplervelocimetry, infra red PCS, time resolved PCS.Author: R. Di Leonardo.Optical Fibers-based Photo-Correlation setup for sheared samples. A photoncorrelationset-up with an optical fiber collecting systemenables measurements on both the dynamicsand the local rheology of a complex fluid. Thesystem is put under shear through a cone-plateor plate-plate cell, whose fixed plate is madeup of an optical window. A polarized laser beam(λ=514 nm) is directed towards the cellcontaining the sample (S) and the scatteredbeam is collected by a mono-mode optical fiber(f 1). Through a beam splitter (BS), part of thelaser beam, representing the local oscillator, iscollected by another fiber (f 2). Both the fibersare polarization-maintaining and theinterference among the scattered field and thelocal oscillator may be achieved through a fiberoptics beam splitter (FOBS), which perfectlymatches the wavefronts of the two beams.Another optical fiber (f 3) propagates theinterfering beam or, optionally, the solescattered beam from the beam splitter to thephotomultiplier. Finally, the digital signal inoutput from the photomultiplier is sent to anhomemade software correlator. In thehomodyne set-up the sole scattered fieldintensity is correlated and information on thedynamics of the system are obtained. In theSOFT Scientific Report 2004-0624

Optical Tweezing Laboratory – UdR RomaHolographic Optical Tweezer (HOT). A mesoscopicobject can be stably trapped in three dimensions by atightly focusing single laser beam. Computer-generatedholograms displayed on liquid crystal spatial lightmodulators (SLM) offer a convenient way of producinglarge three dimensional arrays of optical traps. Theability to dynamically manipulate matter at the mesoscaleopens the way to a wide range of applications inthe physical and biological sciences. We set up aholographic optical tweezers (HOT) apparatus which isshown in Figure. A TEM00 mode beam from a diodepumped, 532 nm, 2 W laser is expanded and reflectedoff a liquid crystal (45° twisted nematic) Spatial LightModulator. Novel techniques for the generation ofhighly optimized holograms have been developed. Thephase modulated wavefront is then imaged onto theexit pupil of a 100x NA 1.4 objective lens mounted in aninverted optical microscope. The same lens is used toimage trapped particles on a software controlled digitalCCD camera. We developed a set of tools to extract andprocess particle trajectories by digital video microscopy.We're working on applications of holographic opticalmicro-manipulation to micro-fluidics, statisticalmechanics, colloidal science and micro-rheology of softmaterials.Non Linear Optics Laboratory – UdR RomaZ-scan set-up The Z-scan is a sensitive andcommonly employed technique able to measureboth nonlinear absorpsion and refraction in solidsand liquids and is based essentially on refractiveindex modulation by laser irradiance on anonlinear material. In this technique a polarizedGaussian laser beam, propagating in the z-direction, is focused to a narrow waist by a lens.The sample is moved along the z-axis throughthe focal point and the transmitted intensity ismeasured, as a function of z-direction in the farfield using a photodiode behind a smallcalibrated pinhole. In this way the trasmittanseis sensible to wave phase shift variations due tothe refractive index gradient induced in anonlinear material. In our set up a CW pumpeddiode laser operates at power 10 mW andwavelenght 532 nm. The beam is focused bymeans of a 75 mm focal lenght lens giving a 20µm beam waist radius and a I 0=8. 10 6 w/m 2beam central intensity at the focus (z=0). Aphotodetector, at distance 310 mm from lensfocus, is used to probe the light power behind a2 mm aperture and the sample is scanned acrossthe focus with a 5 cm micrometer traslationstage. This apparatus allows to measurerefraction index variations due mostly to thermaland electostrictive effects with nonlinearrefraction index n 2 ∼ 10 -6 – 10 -10 cm 2 /W.25SOFT Scientific Report 2004-06

FacilitiesStatic Light Scattering Laboratory – UdR RomaStatic light scattering (SLS). The source is an He-Nelaser beam with a λ=632,8 nm and a rotating harm canexplore angles between 15 and 155 degree. Thiscorrespond to a q range between 0.03-0.003 nm -1 . Apinhole and a lens with f=7.5 mm focalise the beam atthe centre of measurement cell. The scattered light iscollected trough a lens which create an imagine of thescattering volume on a multimode fibre. The intensityof scattered light is then acquired and sent to acomputer.A charge coupled device (CCD) camera has been usedto implement a low angle elastic light scattering setup.The detectable angular range covers ~2 decades, from~0.1° to ~10°. The experimental arrangement is showedin Fig.2. The light source is a 8 mW He-Ne withλ=632,8 nm -1 . The beam is spatially filtered, with asystem of pinhole-lens-pinhole, then expanded to adiameter of roughly 2.5 mm and shined onto thesample which is contained in a square glass cell 10 mmwide. The light scattered by the sample is collected bya lens L1 (F=80 mm, Φ=50 mm) and forwarded ontothe CCD camera. A second lens L2 (a standardphotographic objective Nikon macro 50mm) conjugatesthe plane of the CCD sensor and the focal plane of thel1 lens with a magnification ratio of M=Q 2/P 2 therefore,a one to one mapping between the intensity of the lightscattered at different angles and the signals out fromthe correspondin g pixel is realized. Finally, a beamstop is placed in the focal plane of the l1 lenspreventing the unscattered light from reaching thesensorCalorimetry and Rheology Laboratory – UdR RomaBeside to ancillary instrumentation, the C&R Lab is equipeed with a RheoStress RS150 Haake rheometer (max.torque = 150 mNm, min. torque = 0.5x10-4/0.2x10-4 mnM, max. speed = 1000/min, min. speed = 0.01/min) andwith a Diamond Perkin-Elmer differential scanning calorimeter (temperature range between -100 0 C and730 0 C, cooling rates between 0.01 0 C/min and 500 0 C/min.).SOFT Scientific Report 2004-0626

NMR Laboratory – UdR RomaSingle-sided NMR device. The mq-Profiler (BrukerBiospin, Italy) is an in situ compact NMR relaxometer,equipped with single-sided magnet and interchangeableRF coils for performing 1 H-NMR experiments within 1 cmbelow the surface of arbitrarily shaped samples. Theportable broadbanded electronics unit (weight ~ 10 Kg)to which the probe is connected is based on Bruker’sminispec mq-BB console. The magnet assembly of themq-ProFiler is all included in a volume of about 5 x 5 x10 cm3 and consists of two permanent magnets ofrectangular section, placed in an antiparallelconfiguration and fixed to an iron yoke, which generatea static polarization field (~ 0.4 T). The interchangeableRF coil (Larmor frequency of about 18 MHz) are placedin the space between the magnets and produce theresonant condition at different fixed distances from thesurface of the magnet. Due to the open geometry of thesingle-sided apparatus, strong magnetic field gradients(~ 10 T/m) are present.High Resolution NMR Spectrometer. NMR 300MHz Ultra Shield Bruker spectrometer (probes:cryo, 1 H, BBO). Equipped with a BGU2 gradient unit(max gradient intensity 1200 Gauss/cm). Suitablefor high-resolution spectroscopy on various nuclei( 1 H, 2 H, 17 O, 13 C), molecular motion studies in awide diffusive range (10 -9 – 10 -14 m 2 /s) andstructural analysis (i.e. porous media)27SOFT Scientific Report 2004-06

FacilitiesSpectroscopy Laboratory - UdR TrentoBrillouin e Raman spectroscopywith a SOPRA double monocromatorand single mode Argon laser.Micro-macro Raman SpectrometerJobin-Yvon LabRam with He-Ne laser.NMR Spectrometer Avance 400 Bruker.Ion-trap Mass Spectrometer Bruker Esquire-LC, with electrospray ion source (UdR Trento).Cluster 8 nodi opteron dual-core 2.2 GHz, 4 HD160 GB 4 HD 80 GB, 2 GB RAM per nodo.SOFT Scientific Report 2004-0628

29SOFT Scientific Report 2004-06

LSFSOFT Scientific Report 2004-0630

Activity at Large Scale FacilitiesThese activities are mainly devoted to neutron and x-ray applications at ILL and ESRFfacilities in Grenoble (France). There are several projects concerning instrumentconstruction and improvement as well as development of new devices. Long term projectsare AXES (ESRF), BRISP (ILL), ID16 (ESRF), IN13 (ILL) and the participation to the NMI3initiative of the EU under FP6. The research groups are very active in both scientific andtechnical activities as it is evident also from their participation to the life and conduction ofthe facilities.Participation to various bodies related to the facilities conductionF. Barocchi (NMI3, SAC)L. Braicovich (ESRF Chairman of the Scientific Advisory Committee, SAC, 2002-2005)C. Petrillo (ILL Steering Committee, ESFRI neutron expert group, ESRF SAC member)G. Ruocco (ESRF SAC member, 1997-2005, ESRF President Selection Panel, ESFRI softX-ray expert group, ESRF Council member)F. Sacchetti (ILL Instrument subcommittee)Development of the neutron Brillouin Spectrometer BRISPDuring the last two years the BRISP spectrometer has been completed and tested. BRISP is the onlyreactor-based neutron instrument in the world dedicated to the study of small momentum inelasticscattering. This instrument has a conventional general layout, but it is the only small-angle scatteringspectrometer using thermal neutrons (incident energies above 20 meV). In addition, the primaryspectrometer exploits an innovatory design based on a long converging honeycomb collimator, whichis the first ever employed in the world. This special collimator is a substantial improvement over otherpossible solutions and increases the performances in terms of intensity by about a factor ten. Theoverall BRISP layout is reported in Fig. 1 and the actual situation at the beginning of 2005 is shown inFig. 2.The instrument has successfully passed all the complex safety constraints regarding the radiologicalshielding and conventional structures at a reactor source. The spectrometer has been tested duringthe last 2005 reactor cycle. The tests confirmed the predicted performances in terms of energyresolution, momentum transfer, energy range and intensity. The instrument configuration used duringthis test phase was essentially the final one, except for the detector outer shielding which was notinstalled. The effectiveness of different configurations was verified and led to the definition of anexecutive design of the permanent shielding structure at the detector vacuum tank.Finally, a test experiment has been performed at the end of the last reactor cycle in 2005. Themeasurements were devoted to the study of the dynamic structure factor of liquid Pb at the meltingpoint, and were carried out with a limited and provisional shielding of the detector chamber. Thebackground present in the first measurements is expected to be strongly reduced in the finalconfiguration with complete shielding, which will be available in 2006. This test experimentdemonstrated that the instrument, even in its first configuration, is already competitive in terms ofintensity with the most efficient three axis spectrometer IN8 of ILL.Considering the possible improvements attainable by the construction of a new Fermi chopper, we canalready state that the BRISP spectrometer provides the best performance in the world, when theoverall capabilities in terms of intensity, energy resolution and dynamic range are examined at thesame time and compared with the general performances of other instruments.Few technical details:- available incident energies: 20.1 and 80.3 meV (PG monochromator), 51.9 meV with Cu monochromator- two-dimensional neutron detection between 0.5° and 15° scattering angle- Q el values as low as 0.03 Å -1 @ 20 meV can be reached- peak flux density after neutron monochromatization: 1.5 10 7 n cm -2 s -1- accessible dynamical range: ~ 0.2 < E < 100 meV and ~ 0.03 < Q < 8 Å -1- space and time accessible domains: ~ 0.05 < t < 20 ps and ~ 1 < r < 200 Å(further details can be found at http://www.ill.fr/YellowBook/BRISP and http://infmweb.fi.infn.it/BRISP)31SOFT Scientific Report 2004-06

LSFFig. 1 – BRISP layoutBackground chopperFermi chopperDetector vacuum tankSample chamberPrimary shieldingcontaining Sollercollimator andmonochromatorHoneycomb collimatorDetector beforeinstallationBRISP platformFig. 2 – BRISP at the beginning of 2005Snapshots of BRISP components and development:5000 rpm maxTest of primary shielding - June 2004Background chopper disk and finaldevice assemblySOFT Scientific Report 2004-0632

4321Counts (arb. u.) 5PGη = 0.40ºLarge area graphite monochromator0-1.5 -1.0 -0.5 0.0 0.5 1.0 1.5Rocking angle ωTypical rocking curve ofthe graphite crystalsHoneycomb collimator(transverse cross section view)500 mm550 mm3·10 -6 mbar (isolated)Sample chamberRear part of the detector assembly showingthe electronics chamber (operation foreseesdetector under vacuum and electronics in air)80 3 He tubesIntensity (n cm -2 s -1 )railsenergy chainBeam at the monochromator positionJuly 2004Detector mounted on its translationstage inside the huge vacuum tank33SOFT Scientific Report 2004-06

LSFBRISP first spectraLeft panel: elastic scattering from vanadiumRight panel: constant momentum scan in liquid Pb at 650 KA glance at the final configuration (refinements are in progress):New structure forpolyethylene andboron carbideouter detectorshieldingDetector vacuum tankDirect beamexternal Pb catcherThe instrument technical development and scientific goals have already deserved more than 10publications in international journals, numerous invited talks at international conferences andworkshops, and several presentations at national meetings.SOFT Scientific Report 2004-0634

Development of the neutron backscattering spectrometer IN13IN13 is a backscattering spectrometer working with thermal neutrons with wavelength 2.23 Ǻcorresponding to energy of 16.45 meV (Fig. 1). The tuning of the incident neutron energy is obtainedby adjusting the d-spacing of the monochromator by heating it. The energy resolution is of the orderof 7 µeV and the energy window is ± 150µeV, corresponding to a time scale ranging from 4,5 10 -12 sto 10 -10 s. The instrument fills the energy gap between IN10 or IN16 at ILL and IN5 at ILL, MIBEMOLat the LLB or IRIS at the Rutherford-Appleton laboratory (RAL) in United-Kingdom. In addition thevalue of the incident energy gives the availability of high momentum transfers (Q

LSFNeutron guideMonochromator crystalGraphiteDeflectorHelium gas filledflightpathCryofurnace01 mChopper housingFig. 1 Schematic view of IN13MonitorSampleDetector modules5 x 5 detectorsAnalyser crystals( 2 plates )Three concentric ringsof analyser crystalsPosition sensitivedetector ( 2048 cells )Analyser crystals( 5 plates )Detector modules2 x 5 detectorsShieldingBeam stopFig. 2: comparison between the old and new configurations of the IN13 second spectrometer.A schematic plan is accompanied in both cases by pictures.The old IN13 configurationThe new IN13 configurationSOFT Scientific Report 2004-0636

Fig. 3: Plan of the Position Sensitive Detector (panel a) and picture of the realisedcomponent (panel b): 2 x8 position sensitive detection tubes symmetrically set withrespect to the incident neutron beam.Fig 4: Drawing of the Position Sensitive Detector assembly (panel a)showing the mechanics ofthe active part (tubes), that supports the primary collimator and the front end conically shapedcollimator (panel b).37SOFT Scientific Report 2004-06

LSFAXES: Advanced X-ray Emission SpectroscopyThe main apparatus is AXES (Advanced X-Ray Emission Spectrograph) permanently installed at thepublic beamline ID08 of the ESRF-GrenobleTECHNIQUES• Resonant Inelastic X-Ray Scattering (RIXS)• Fluorescence Spectroscopy-Integrated Resonant Raman Scattering (IRRS)• X-ray Absorption Spectroscopy (XAS)• X-ray Magnetic Circular Dichroism (XMCD)• Dichroism in RIXS• Dichroism in IRRS-Polarisation analysis of scattered photons• Resonant Photoemission• Spin resolved photoemission• High Energy Photoemission with soft & hard X-raysONGOING and PLANNED RESEARCH ACTIVITIES• High resolution RIXS from cuprates and manganites at RT (at present) and at low T• High resolution RIXS from compounds of light Rare Earths• Symmetry breaking effects in Resonant Raman Scattering from:ooMagnetic systems (circular dichroism in perpendicular geometry)Non-magnetic strongly correlated systems (lin. dichr.)• Application of sum rules to RIXS and IRRS (instrument improvement also planned)• Fast collision approximation and beyond• Buried InterfacesSOFT Scientific Report 2004-0638

Co-ferrite IRRSIntensity (arb. units)L 3L 2Circ. Dichr.780 790 800 810Incident Photon Energy (eV)Sum Rules in IRRSL.Braicovich et al. Phys. Rev. Lett. 90,117401 (2003)RIXS in HighTc superconductorsG. Ghiringhelli et al. Phys. Rev. Lett. 92,117406 (2004)10 vertical polarisationL 3 RIXShorizontal polarisationMnOIntensity (photons -1 s eV -1 )86420edcba-6 -5 -4 -3 -2 -1 0relative scattered photon energy (eV)L 3 XASedcba646645644643642641640639638incident photon energy (eV)PARTICIPANTS to AXESL. BraicovichC. DalleraG. GhringhelliA. TagliaferriA. Piazzalunga PhDF. Fracassi PhDTechnical support byOGG technicians andPolitecnico Milano techniciansRecent Improvements in RIXS resolution39SOFT Scientific Report 2004-06

LSFID16: Inelastic X-ray ScatteringIn 1993 started a collaboration (formerly called BL21) between the researchers of the Inelastic X-rayScattering group at ESRF and those of the INFM at the UdR-AQ. The aim of the collaboration –that isnowadays ruled by a formal contract between ESRF and INFM-CNR- was to realise a spectrometercapable of probing the atomic dynamics of disordered condensed matter in the mesoscopic space-timedomain, i.e. for exchange momentum, Q, ranging from 1 to 10 inverse nm, and for exchangedenergy, E, in the 1 to 20 meV range. The dynamics of density fluctuations in this momentum-energyregion, can be assessed by the experimental determination of the dynamic structure factor, S(Q,E).Traditionally, this is the domain of neutron spectroscopies. The inelastic neutrons scatteringtechniques, however, due to well-known kinematic limitations, were not easily applied to disorderedsystems, like liquids and glasses, with a large velocity of sound. The kinematical limitations ofneutrons do not apply to inelastic x-ray scattering, and therefore the latter technique can be utilisedto directly measure the S(Q,E) of disordered systems. There were, however, severe problems thatneeded to be solved in order to achieve the necessary energy resolution of few meV.As a result of the collaboration a high energy resolution x-ray spectrometer was available; it was oneof the three spectrometers of the public beamline ID16 at ESRF, at that time headed by FrancescoSette. This instrument has opened new frontiers in the physics of disordered materials. In particular, ithad made accessible the direct experimental determination of the dynamic structure factor S(Q,E) ofdisordered systems (liquid, glasses, dense fluids) in a Q-E region which, as mentioned before, waspreviously inaccessible to other techniques.A crucial part of the spectrometer, namely the 7 m long analyser arm and its instrumentation, wasconstructed through a scientific collaboration between the ESRF and the INFM/Udr AQ. The operationof the instrument, within the context of this collaboration, has produced important results on issues asthe high frequency collective dynamics in water, glasses, and glass former liquids (see the enclosedpublication list). Moreover results have been also obtained in many other fields, like, for example, thedense fluids at very high pressures and the collective properties of biological materials.At the end of 1996 a first upgrading of the spectrometer, partially founded by INFM, has beenrealised. It consists in the implementation on the 7 m arm of five analysers operating simultaneouslyat different scattering angles, and therefore this allows one to determine the S(Q,E) at five differentQ-values at the same time. The possibility of data acquisition with much improved statistics inreasonable time (about one week for a typical experiment) has opened the possibility to studyproblems which were very difficult before (temperature and pressure dependencies, phase transition,small samples, heavy elements,...).In the Soft “period”, the ID16 (former BL21) collaboration entered as one of the activities which isgoing on in the CRS. It still continue to produce important scientific results (see the publication list)and is the formal base for a continous exchange of students (both Laurea and PhD students),PostDocs and Scientists.Images of the ID16 beamline taken from the ESRF website, www.esrf.fr.SOFT Scientific Report 2004-0640

41SOFT Scientific Report 2004-06

LSFExperiments at LSFYear 2004Elettra - IUVS• Confined Water• IUVS Brillouin scattering from liquid Glycerol• High-resolution Ultra-Violet investigation of the attenuation of acoustic modes in glycerolEMBL Hamburg• Role of metals in the process of amyloid beta peptide polimerisationESRF – BM10B• Geometry of MnO6 octahedra in Ni doped (La0.63Ca0.37)MnO3 compounds as a function of temperatureESRF – BM29• Strain distribution in granular matter subject to high-pressure: a combined XAFS and ESXD experiment• Post-melting anomalies in Pb-Sn and In-Sn alloys under extreme conditions• Liquid and solid bismuth under pressure: undercooling and polymorphismESRF – BM30B• Role of metals in the process of amyloid beta peptide polimerisationESRF – ID16• Effects of gelation and chemical vitrification on the high-frequency collective dynamics of epoxy-amine• High frequency acoustic modes in the intermediate glass forming system treithol• Search for an isothermal regime bridging the hydrodynamic and the high frequency in liquid metals• High frequency dynamics in metallic glasses• High frequency relaxations in a transition liquid metal• IXS scattering study of the amorphous-to-crystalline and ferroelectric phase transition in GeTe• IXS study of the collective dynamics of K-NH 3 solutionsESRF – ID28• Role of the orientational disorder in the high frequency dynamics of plastic crystals: the case of o-carborane• Microscopic dynamics in binary ionic mixtures: the case of LiFILL - D11• Structural properties of cellulose in ancient paper with different state of degradationILL-D1A• Study of charge ordered/ferromagnetic-metallic phase in (Pr0.55Ca0.45)(Mn1-yCry)O3 manganites• Competition between orbital ordering and charge delocalisation in Cr-doped manganites• Antiferromagnetic-charge ordered/ferromagnetic-metallic phase separation in (La 1-xCa x)(Mn 1-yCu y)O 3ILL - D1B• First sharp diffraction peak in alkaline borate glasses• Crystalline bundles, capillarity & wetting in Carbon nanotubes• Phase transitions in liquid Deuterium under nanotube confinementILL-D16• Diffraction from crystalline bundles of single wall carbon nanotubesILL-D20• Transition from ferromagnetism to cluster-glass behaviour in Ln 0.7Pb 0.3Mn 1-xFe xO 3 perovskiteILL - IN1• Coexistence of two density fluctuation modes in molten Li-Bi alloys: the role of concentrationILL - IN3• Low-density hydrogen as a possible calibration standard for small-angle inelastic spectroscopyILL - IN5• Coherent excitations in phosphate glasses• Large Q-ω range investigation in the field of biological physics• Incoherent quasi-elastic neutron scattering study of water confined in silica hydrogels• Microscopic spin hamiltonian and magnetic anisotropy of heterometallic Cr7M wheels• Fast internal dynamics of folding states of small globular model proteinsSOFT Scientific Report 2004-0642

LL – IN6• Fast internal dynamics of folding states of small globular model proteinsILL - IN8• Coherent ion dynamics of isotopic liquid cadmiumILL - IN10• High temperature dynamical transition in beta-lactoglobulinILL – IN11• Large Q-ω range investigation in the field of biological physics• Low energy spin dynamics in CMR manganitesILL – IN12• Large Q-ω range investigation in the field of biological physicsILL – IN13• Large Q-ω range investigation in the field of biological physics• Effect of pressure on the conformational dynamics of globular proteinsand simple sugars• Dynamics of membranes• Dynamics at low angle scattering in oriented membranes• Proton mobility in different types of hydrated seeds• Dynamics of hydrated saccharides• Study of the diffusive dynamics in cryo- and crypto protectans/H2O mixtures• Incoherent quasi-elastic neutron scattering study of water confined in silica hydrogelsILL – IN16• Large Q-ω range investigation in the field of biological physics• Fast internal dynamics of folding states of small globular model proteins• Spin dynamics in a frustrated molecular nanomagnet• Translational dynamics of water confined in silica hydrogels in the nanosecond time scaleISIS - VESUVIO• DINS investigation of anisotropic dynamics in a model of a biological membraneInstitut fur Festkorperforschung (SANS)• Micelles of Mono or Bifunctional Perfluoropolyether Surfactants in WaterLab. Leon Brillouin CEA-CNRS (SANS)• Aqueous Micellar Solutions of Mono or Bifunctional PFPE SurfactantsSpring8• IXS study of secondary modes in the high frequency dynamics of liquid Gallium43SOFT Scientific Report 2004-06

LSFYear 2005Elettra - IUVS• High frequency acoustic modes in the intermediate glass forming system threitol• Propagation and attenuation of high frequency acoustic modes in vitreus silica• Inelastic Ultra-Violet Scattering Investigation of the transverse dynamics of water• Investigation of the dynamic contribution to the sound attenuation in vitreous silica• Brillouin ultraviolet light scattering on vitreous beryllium fluoride• Inelastic Ultra-Violet Scattering Investigation of the phonons mean free path in glassy GlycerolESRF – BM29• Icosahedral short range ordering in molten and undercooled transition metals• Study of fuel cells catalysts atomic structure using x-ray absorption spectroscopyESRF – ID09A• Study of the high P-T phase diagram of crystalline polyethylene by X-ray diffractionESRF - ID09B• Time-resolved diffraction study of Azobenzene photoisomerizationESRF - ID10B• Structural and morphological modifications induced by the interaction of MBP with charged and neutralphosphlipid monolayersESRF - ID16• Pressure-induced vitrification in epoxy systems in the mesoscopic Q-range• IXS investigation of dynamics in a photosensitive poly-azo-acrylate glass-former• High frequency dynamics of liquid ammonia as a function of pressure and temperature• IXS study of the collective dynamics of the binary liquid alloy Li 0.8Mg 0.2ESRF – ID27• Study of the high P-T molecular-nonmolecular transformation of carbon dioxide by X-ray diffraction•ESRF – ID28• Study of the high P-T molecular-nonmolecular transformation of CO 2 by inelastic X-ray scattering• The collective atomic dynamics in liquid Na(x)Sn(1-x) alloys• Role of the orientational disorder in the high frequency dynamics of plastic crystals: o-carboraneILL – D7• Inhomegeneous magnetism in Fe-doped CMR perovskite• Short range magnetic correlation of magnetic in Cr based single magnet ringsILL - D10• Preferential site occupancy and magnetic properties of Ni Mn Ga shape-memory alloysILL - D16• Generation of crystalline bundles in single wall carbon nanotubes samplesILL - D1A• Phase separation in Mn substituted (La 0.25Ca 0.75)(Mn 1-yM y)O 3 manganites (M = Cu or Ni)• Effect of Ni-substitution at the Mn-site of (La 0.50Ca 0.50)(Mn 1-xNi x)O 3ILL - D1B• Crystallization behavior of confined D2 within carbon nanotubesILL-D20• Effect of Ru substitution on the magnetic ordering in La 0.6Pb 0.4Mn 1-xRu xO 3 (0.2

ILL – IN4• Microscopic collective excitations in liquid para-H 2 under confinementILL - IN5• Dynamical transition of water confined on Nafion membrane. A quasielastic neutron scattering• Dynamic Behavior of a Hyperthermophilic Protein using Quasi-Elastic Neutron Scattering• Dynamic properties and structural stability of myoglobin embedded in silica hydrogelsILL – IN8• Collective magnetic excitation modes in nearly optimally doped bilayer superconductor Bi 2Sr 2CaCu 2O 8+d• The magnetic resonance peak in the bilayer highly overdoped Bi 2Sr 2CaCu 2O 8+d systemILL - IN13• The Debye-Waller factor approaching the glass-transition temperature in v-GeO 2ILL – IN22• Magnetis excitations in Ca 2+xY 2-xCu 5O 10HMI - NEAT• Directional dynamics in DMPC membranes containing gangliosides45SOFT Scientific Report 2004-06

LSFYear 2006Elettra - IUVS• Study of the influence of trehalose on the structural dynamics of water trehalose mixturesBENSC - NEAT• Fast dynamics of glass-forming sorbitol as a function of the temperature)EMBL Hamburg• Role of metals in the process of amyloid beta peptide polimerisationESRF – ID2• Distinguish between glass and gel phase in a charged colloidal systemESRF – ID09B• Time-resolved diffraction study of Azobenzene photoisomerizationESRF - ID10A• XPCS study of slow dynamics in a photosensitive poly-azo-acrylate glass-former•ESRF - ID10B• DNA surfactant interaction at the air-water and solid-water interfacesESRF - ID16• High frequency dynamics in 3-methylpentane• IXS investigation of the structural arrest in the living polymer alpha-methylstyrene• Role of the disorder in the high frequency dynamics of liquid crystal: the case of 5CBESRF – BM26• Structural determination of the liquid-liquid phase transition in a 4-methylpiridyne/alphacyclodextrin/watersolutionILL - D16• Small angle neutron scattering analysis of (Pr 0.55Ca 0.45)(Mn 1-yCr y)O 3ILL - D1A• Spin coupling and evolution of nuclear and magnetic structures in Cr substituted (La,Ca)MnO 3 compounds• Effect of Ru-substitution at the Mn-site of (La 1-xCa x)(Mn 1-yRu y)O 3 onthe magnetic phase separationILL - D7• The role of rare earth in the physical properties of half doped CMR perovskiteILL – D10• Incommensurate magnetic order in the spin 1/2 chain compound NaCu 2O 2ILL – D11• Small angle neutron scattering study of zirconium phosphate/Nafion composite membranes for fuel cellsILL - D20• Characterization of MgB 2 compounds• Energy dissipation mechanism in Magnetic Shape Memory Alloys - polymer composites• Phase transitions of Deuterium under Carbon Nanotube induced confinementILL - IN1• Collective density fluctuations in deuterated liquid sulphuric acid• Low energy spin dynamics in La0.7Pb0.3Mn1-xFexO3 manganitesILL - IN3• Damping mechanisms and the collective dynamics of liquid ND 3• Propagation of collective excitations in liquid d-hexaneSOFT Scientific Report 2004-0646

ILL - IN5• The anomalous behavior of single molecule diffusion in liquid water• Internal dynamics of myoglobin immobilised on phosphate grafted-Zirconia nanoparticles• Dynamics in heterogeneous systems : study of the confined water in reverse micelles• Effect of negative solubility on the solvent mobility in the binary mixture a-cyclodextrine- 4 methylpyridine.ILL - IN10• Protein dynamics in the temperature range below the dynamical transition.ILL - IN13• Protein dynamics in the temperature range below the dynamical transition• The dynamic transition of myoglobin encapsulated in silica hydrogel is solvent induced?• Microscopic dinamics approaching the glass-transition temperature in borate glass• Stress resistance dynamics of Coccomyxa under irradiation and metallic toxicity• Directional dynamics in single andbicomponent lipid membranes: effect of hydration• Low energy dynamics of PEG in presence of trehalose• Study on dynamics of dUTPase-complex in presence of trehalose• Study of biopolymers as a functionof concentrationISIS - TOSCA• Dynamic of cellulose in ancient paper with different state of degradationISIS - INES• Structure of cellulose in ancient paper with different state of degradation• The role of rare hearth in the physical properties of half-doped manganitesLLB – G6.1• High pressure study of magnetic order and phase diagram of La 0.75Ca 0.25MnO 347SOFT Scientific Report 2004-06

Scientific ReportsScientific ReportsNon-Equilibrium Dynamics and ComplexityLight and Complexity 50Phase Transitions and Topology 51High Frequency Dynamics in Disordered Systems 52Phase Diagram of a Solution Undergoing Inverse Melting 53Brillouin ultraviolet light scattering on vitreous silica 54Packing vs. Temperature Effects in Polymers 55A Manifestation of the Ostwald Step Rule: The Free-Energy Landscape of Polyethylene Xtals 56Instrumentations and Methods for Nanotechnology 57The Molecular Mechanism of Muscle Contraction 58Time Resolved X-rays Scattering from Disordered Systems 59Glass transition in Photosensitive Polymers 60Polarization Fluctuation and Dissipation in Out of Equilibrium Systems 61Relation Between Thermodynamic and Dynamic Properties in Glass Formers 62High-frequency dynamics of v-GeO 2 63Brillouin visible and ultraviolet light scattering measurements in v-SiO 2 and silica porous systems 64Microscopic Dynamics in Liquid Metals 65Non-Ergodicity in Locally Ordered Systems 66Nonlinear Optics in Soft-Matter 67Colloidal Suspensions Under Shear 68Multi-point Holographic Optical micro-Velocimetry 69Polymeric Elements For Adaptive Networks 70Aging of the Nonlinear Optical Susceptibility 71Rubberlike Dynamics in Sulphur Above the λ-Transition Temperature 72Tackling the λ-transition in liquid Sulphur by InfraRed Photon Correlation Spectroscopy 73Vibrational Dynamycs and Viscous Flow in Glass Forming Liquids 74The low-energy excess of vibrational states in v-SiO2: the role of transverse dynamics 75Droplets of Liquid Gallium Under High Temperature and High Pressure Conditions 76Vibrational properties of inclusion complexes: the case of indomethacin-cyclodextrin 77Temperature-dependent vibrational heterogeneities in harmonic glasses 78Aging in Charged Colloidal Systems 79Matter Under High Pressure 80From Bulk to Nano-Structured Liquids 81SOFT Scientific Report 2004-0648

Self Assembly, Clustering, Structural arrestBiopolymer-Vescicle Interactions 85Polyelectrolyte-Liposome Complexes: Evidence of Equilibrium Multi-Compartment Aggregates 86Dielectric Properties of Polyelectrolyte Aqueous Solutions: the Scaling Approach 87Aging of aqueous Laponite suspensions studied by 23 Na Triple-Quantum NMR spectroscopy 88Clustering and Cooperative Dynamics in Reactive Mixtures 89Role of metal ions in protein aggregation processes 90Role of water around biomolecules and surfactants 91Multi-Scale Simulations of Macromolecular Systems 92Investigation of the Relation Between Local Inherent Structures Properties and the Diffusivity 93Coil-Globule Transition of DNA Molecules Induced by Cationic Surfactants 94Multi-Scale Coarse-Graining of Diblock Copolymer Self-Assembly 95Bernal Spiral Clusters in Colloid-Polymer Mixtures 96Molecular Clustering by High Resolution NMR 97Non-invasive 1 H-NMR in porous materials of artistic interest 98Elastic and anelastic scattering of neutrons and X-raysIon Density Fluctuations in Liquid Gallium 99Femtosecond dynamics in Ferromagnetic Metals 100Soft Resonant X-ray Scattering 101Picosecond-Timescale Fluctuations of Proteins in Glassy Matrices: The Role of Viscosity 102Neutron inelastic scattering on liquid CD 4 : a probe of the dynamics in simple molecular liquids 103The Dynamics of Dilute H 2 Enabling New Calibration Methods in Neutron Spectroscopy 104Effect of Solvent and of Confinement on the Dynamics of Hydrated Proteins 105Dynamics in Model Membranes, Membrane-Protein and Membrane-DNA Interactions 106Dynamics of Hydrated Saccharides and Saccharide Gels 10749SOFT Scientific Report 2004-06

Scientific Report – Non Equilibrium Dynamics and ComplexityLight and ComplexityIn a nutshell, a random laser is a disorderedamplifying optical cavity emitting coherent radiation.The system can be realized by artificial nanostructuredoptical devices, or can be a self-organizeddispersion of particles in the multi-scattering regime.In both cases, optical gain can be obtained with theaddition of some active materials, like dyes orquantum dots. Random laser emission is stronglyaffected by the structure and the history of thematerial, hence it is an original and multidisciplinaryapproach for the investigation of soft-matter.Additionally, this kind of lasers strikingly displaysthose ingredients which are typical of the physics ofcomplexity: randomness and nonlinearity.In Refs. [1], it has been shown that theory ofrandom laser can be reformulated as mean field spinglass theory and a series of new physical processes,including for example a “glassy behaviour of light,”have been predicted. Such an approach open newopportunities for testing the modern theory ofcomplexity, and conceiving new experiments on theglass transition which should enable to investigatenew previously un-accessible regimes, due to theintrinsically fast dynamics of a “photon glass.”Specifically, a random optical cavity is characterizedby N resonant modes with angular frequencies ω nand complex amplitudes a n, (n=1…N); such that theenergy stored into each mode is ω n|a n| 2 . Laser theorysays that the moduli of the a n are slowly varying withrespect to the phases ϕ n, hence the former can betaken as quenched variables while the latter are therelevant dynamic variables and take the role ofspherical spins. The Hamiltonian is:∑H = cos( ϕ + ϕ −ϕ−ϕ)J spqrspqwhere the random coupling constants J aredetermined by the spatial overlap of the resonantmodes. The replica method is applied for determiningthe energy landscape of the model and the existenceof a one-step replica symmetry breaking (1RSB), orglass-transition. The role of the inverse temperatureis played by the ratio between the squared averageenergy stored into each mode and the amount ofnoise due to spontaneous emission. There exist acritical value of this effective temperature for theexistence of an exponentially large number of metastablestates, each corresponding to a differentrFig. 2: Ab initio 3D+1 computation of specklepatterns at 532nm obtained when light propagatesin high concentration colloidal materials, whosestructure is determined by molecular dynamicsimulations. These numerical techniques providenew opportunities for the investigation of softmaterialproperties, as they may enrich theinformation that can be extracted by experiments inthe multiple-scattering regime.mode-locking process of the random laser. In thisway the complexity (i.e. the configurational entropy)of light in random lasers can be calculated, and thecritical temperature is expressed in term ofexperimentally accessible quantities.Complex dynamics of light is also found, theoreticallyand experimentally, when focused laser beamspropagated in soft-matter like liquid crystals. [2] Inthis case, disorder and nonlinearity contribute to thegeneration of multiple light filaments whosedynamics can be described by the same paradigmsof the physics of soft-matter. Understanding theseprocesses is relevant for various applications, fromall optical digital devices to laser surgery.Photonics in disordered or structured systems,(“complex photonics”) is a very active andmultidisciplinary research field, to which we are alsocontributing by developing new computationalapproaches (figure 1), and designing novel opticaldevices [3] (as e.g. “photonic crystals”) which can beinfiltrated by soft-materials, and provideopportunities for femtoliter substance analysis.References[1] L. Angelani, C. Conti, G. Ruocco, F. Zamponi,Phys. Rev. Lett. 96, 065702 (2006); Condmat/0511427;L. Angelani, C. Conti, G. Ruocco, F.Zamponi, cond-mat/0604242, submitted to Phys.Rev. B[2] C. Conti, Phys. Rev. 72, 066620 (2005); C.Conti, M. Peccianti, G. Assanto, Opt. Lett. (2006),submitted.[3] A. Di Falco, C. Conti, G. Assanto, Appl. Phys. B81, 415 (2005); A. Di Falco C. Conti, G. Assanto,Opt. Lett. 31, 250 (2006); A. Di Falco C. Conti, G.Assanto, Opt. Lett. (2006), submittedFig. 1: Relevant overlap of the spin glass theoryof random lasers and complexity Vs the effectivetemperature (from Ref. 1)AuthorsL. Angelani (a), C. Conti (b,c), G. Ruocco (c) , F.Zamponi (d), G. Assanto (e), M. Peccianti (e)(a) SMC INFM-CNR (b) Research Center EnricoFermi (c) SOFT INFM-CNR (d) Ecole NormalSuperiore (e) University Roma Tre.SOFT Scientific Report 2004-0650

Phase Transitions and TopologyPhase transitions are a very well understood subjectin statistical mechanics and a huge amount of workhas been done in the last century. Recently,however, a novel characterization of phasetransitions has been proposed [1]: the singularbehaviour of thermodynamic observables at a phasetransition is attributed to major topology changes inphase space or, equivalently, in configuration space.More precisely, the conjecture is that for a systemdefined by a continuous potential energy functionV(q) – q denotes the N-dimensional vector of thegeneralized coordinates – a thermodynamic phasetransition occurring at T c (corresponding to energyV c) is the manifestation of a topological discontinuitytaking place at the specific value V c of the potentialenergy function V (strong topological hypothesis).The most striking consequence of this hypothesis isthat the signature of a phase transition is present inthe topology of the configuration spaceindependently on the statistical measure defined onit. Through Morse theory, topological changes arerelated to the presence of stationary points of V,and, more specifically, to the discontinuousbehaviour of invariant quantity defined on them, asthe Euler characteristic χ.However, there are many open questions. Amongthem: what are the necessary and/or sufficiencyconditions for the topological hypothesis? What is theexact correspondence between the thermodynamicand the topological transition points? What about theorder of the phase transition?On the one hand, there is a theorem [1] assertingthat, for smooth, finite-range and confininginteraction potentials a topology change at some V θis a necessary condition for a phase transition totake place at the corresponding energy value. On theother hand, there are numerical studies of variousmodels for which a variety of results has beenobtained.Our main contributions to this topic can besummarised as follow.1. By studying an analytically solvable mean-fieldmodel with k-body interaction (k-trigonometricmodel [2]), that, according to the value of k,undergoes no (k=1), second-order (k=2) or firstorder(k>2) phase transition, we were able todirectly relate the different thermodynamicbehaviours to the Euler characteristic (see Figure 1),finding that the discontinuity of χ signals thepresence of the phase transition and the concavityits order.2. There is a non-trivial relation between the phasetransition critical energy (V c) and the topologicalcritical energy (V θ). By studying different modelsystems (mean-field Φ 4 [3], two one-dimensionalmodels [4]), we found that the relevant topologicalpoints are the “underlying stationary points”(saddles), defined through a map V s=M(V) fromenergy level V to stationary point energy V s. If thereis a topological singularity at V θ a phase transition isFig. 1: Logarithmic Euler characteristic as afunction of potential energy V for the k-trigonometric model with k=1,2,3.also present if and only if there is a temperature T csuch that V s(T c)= V θ (weak topological hypothesis).Our findings seem to indicate that a sufficiencycriterion for the phase transition to take placerequires the introduction of a statistical measure, asthe map M is defined through an average over thestatistical measure. Moreover, the introduced weaktopological hypothesis, based on the concept ofunderlying saddles (well known from glassysystems), appears as a possible framework to fit theresults of a variety of model systems.We hope that this approach can be of interest from atheoretical point of view, in elucidating the deepunderlying relationship between phase transitionsand topology, and from a practical reason, for theinvestigation of mesoscopic systems (e.g. proteinsand large molecules) where the number of degreesof freedom is small enough to detect the presence ofa phase transition using standard techniques.References[1] L. Casetti, M. Pettini, and E.G.D. Cohen, Phys.Rep. 337, 237 (2000); R. Franzosi and M. Pettini,Phys. Rev. Lett. 92, 060601 (2004).[2] L. Angelani, L. Casetti, M. Pettini, G. Ruocco, andF. Zamponi, Europhys. Lett. 62, 775 (2003) ; Phys.Rev. E 71, 036152 (2005).[3] A. Andronico, L. Angelani, G. Ruocco, and F.Zamponi, Phys. Rev. E 70, 041101 (2004).[4] L. Angelani, G. Ruocco, and F. Zamponi, Phys.Rev. E 72, 016122 (2005).AuthorsL. Angelani (a), G. Ruocco (b,c), F. Zamponi (b,d)(a) CRS SMC-INFM-CNR, Roma, Italy(b) CRS SOFT-INFM-CNR, Roma, Italy(c) Dip. di Fisica, Univ. di Roma La Sapienza, Roma,I(d) Ecole Normale Superieure, Paris, France.51SOFT Scientific Report 2004-06

Scientific Report – Non Equilibrium Dynamics and ComplexityHigh Frequency Dynamics in Disordered SystemsThe discovery that disordered materials, such asglasses and liquids, support the propagation of soundwaves in the terahertz frequency region has renewedinterest in a long-standing issue: the nature ofcollective excitations in disordered solids. From theexperimental point of view, the collective excitationsare often studied through the determination of thedynamic structure factor S(Q,ω), i.e. the timeFourier transform of the collective intermediatescatteringfunction F(Q,t) which, in turn, is the spaceFourier transform of the density self-correlationfunction. S(Q,ω) has been widely studied in the pastby the Brillouin light scattering (BLS) and inelasticneutron scattering (INS) techniques. Thesetechniques left an unexplored gap in the Q-space,corresponding to exchanged momentum approachingthe inverse of the inter-particle separation a (themesoscopic region, Q=1–10 inverse nm). This Qregion is important, because here the collectivedynamics undergoes the transition from thehydrodynamic behaviour to the microscopic singleparticleone.Investigation of S(Q,ω)in this mesoscopic region hasbecome possible recently thanks to the developmentof the IXS technique; many systems, ranging fromglasses to liquids, have been studied with thistechnique [1-8]. In addition to specific quantitativedifferences among different systems, all the systemsinvestigated show some qualitative common featuresthat can be summarized as follows:(i) Propagating acoustic-like excitations exist up to amaximum Q-value Q m (aQ m≈1–3 depending on thesystem fragility), having an excitation frequencyΩ(Q). On increasing Q there exists a positivedispersion of the sound velocity (Fig. 2).(ii) Ω(Q) versus Q shows an almost linear dispersionrelation, and its slope, in the Q0 limit, extrapolatesto the macroscopic sound velocity.(iii) The width of the Brillouin peaks, Γ(Q), follows apower law, Γ(Q)=DQ α , with α=2 within the currentlyavailable statistical accuracy (Fig. 1).(iv) The value of D does not depend significantly ontemperature, indicating that this broadening (i.e. theFig. 2: (A) Excitation energy Ω(Q) for vitreous silicafrom IXS (full dots) [2] and MD (open dots) [1].The upper curve is for the L-mode, the lower one isfor the T-mode.; (B) Apparent sound velocity from(A) defined as Ω(Q)/Q.sound attenuation) in the high-frequency region doesnot have a dynamic origin, but is due to the disorder.(v) Finally, at large Q-values, a second peak appearsin S(Q,ω) at frequencies smaller than that of thelongitudinal acoustic excitations. This peak can beascribed to the transverse acoustic dynamics, whosesignature is observed in the dynamic structure factoras a consequence of the absence of pure polarizationof the modes in a topologically disordered system.References[1] O. Pilla et al. J. of Phys. C. M. 16, 8519 (2004).[2] B. Ruzicka, et al. PRB 69, 100201 (2004).[3] T. Scopigno, et al. PRL 92, 025503 (2004).[4] R. Angelini, et al. PRB 70, 224302 (2004).[5] T. Scopigno, et al. PRL 94, 155301 (2005).[6] E. Pontecorvo et al. PRE 71, 011501 (2005).[7] T. Scopigno et al. PRL 96, 135501 (2006)[8] C. Masciovecchio et al. preprint (2006).Fig. 1: Excitation broadening (Γ) vs. excitationenegy position (Ω) square in glassy Selenium [3].AuthorsR. Angelini (a), M. Krisch (c), C. Masciovecchio (b),G. Monaco (c), Pontecorvo (a,d), G. Ruocco (a,d), B.Ruzicka (a), E. T. Scopigno (a), F. Sette (c).(a) CRSSOFT-INFM-CNR, Roma, Italy (b) Elettra, Trieste,Italy (c) ESRF, Grenoble, France (d) Dip. Di Fisica,Univ. Di Roma, Roma, Italy.SOFT Scientific Report 2004-0652

Phase Diagram of a Solution Undergoing Inverse MeltingDifferent theoretical models have been recentlyproposed to describe the counterintuitive phenomenaof inverse melting and inverse freezing [1-4]. Theseinverse transitions happen when a liquid heated atconstant pressure undergoes a reversible liquid solidtransition generating a solid with entropy higherwith respect to its liquid counterpart. A new liquidsystem showing this kind of phenomenology atnormal pressure and in conditions easily reachableexperimentally has been recently found [5]. It is asolution of α-cyclodextrin (αCD) (C 36H 60O 30), waterand 4-methyl-piridyne (4MP) (C 6H 7N) which in propermolar ratio give rise to the phenomenon of inversemelting. Differential scanning calorimetric (DSC)measurements have been performed with a DiamondPerkin-Elmer calorimeter to characterize the inversetransition of these solutions from an energetic pointof view. The thermograms, i.e. the heat flow (dH/dt)as a function of the temperature, reported in Figure1 have been obtained at a heating rate r = 10 K/min.Depending on the concentration, one, two or threepeaks of endothermic nature are observed. The peakand onset temperatures associated to each transitionare reported in Figure 2. At high concentrations ofαCD (right side of the phase diagram of Figure 2)three endothermic peaks are present: the firstcorresponds to a liquid solid phase transition typicalof those systems undergoing inverse melting; theintermediate one has been attributed to a solid solidphase transition and the third one is associated to asolid liquid transition as also observed by naked eye.The DSC data show a perfect agreement with theliquid solid transition temperatures determined withelastic and quasielastic neutron scatteringheat flow dH/dt (mW) Endo up1.00.50.00.01.00.50.50.00.20.01:6:951.01:6:800.51:6:701:6:501:6:40310 320 330 340 350 360 370 380T(K)Fig. 1: DSC thermograms of solutions of αCD,water and 4MP at different concentrations withmolar ratio 1:6:x respectively (40

Scientific Report – Non Equilibrium Dynamics and ComplexityBrillouin ultraviolet light scattering on vitreous silicaSound absorption properties of amorphous solidshave been widely investigated in the last decades;these systems are characterized by a much largersound attenuation coefficient when compared to thecorresponding crystals, and the mechanismsinvolved in sound absorption are still poorlyunderstood. Vitreous silica is a strong glass, andmany techniques have been used to investigate itsdynamics.Fig. 2 - DHO-deconvoluted signal obtained by fittingthe Stokes peak. Dashed: laser, T= 230 K, Q =0.078 nm -1 , peak position: 287.5 µeV, FWHM = 3.0µeV; continuous: synchrotron, room temperature, Q= 0.11 nm -1 , peak position: 438.5 µeV, FWHM = 5.3µeV.An example of experimental spectrum is reported inFig. 1, while examples of deconvoluted Brillouinspectra are shown in Fig. 1, at exchanged momentaQ = 0.078 (laser) and 0.11 (synchrotron) nm -1 .Fig. 1 - Experimental spectrum (circles) withsynchrotron excitation.Ultrasonic attenuation and Brillouin light scatteringshow that, in the respective ranges (kHz-GHz), thesound attenuation is temperature dependent and,thus, due to dynamical processes (typically,anharmonicity). More recently, the use of inelastic X-ray scattering (IXS) at much higher frequencies(THz) showed a T-independent attenuation inducedby the presence itself of structural disorder.Theoretical models and numerical simulations havebeen proposed to describe the transition from thedynamical regime to the static one that dominates inthe region investigated by IXS.We have recently performed [1] measurements inthe intermediate region; the measurements werecarried out at the new inelastic ultraviolet beam line(IUVS) of the Elettra synchrotron radiation facility inTrieste. The IUVS beam line operates usingsynchrotron radiation, with wavelength tunable inthe previously unexplored range 260-110 nm andwith a very high photon flux. A relative energyresolution of 1.1 * 10 -6 was achieved. Alternatively,the instrument can be used with an ultraviolet lasersource, i.e. a frequency-doubled 488 nm single modeAr laser. Backscattering geometry was used, with ascattering angle of about 176 degrees.The Brillouin spectrum directly provides the dynamicstructure factor, S(Q,E), whose width of is related tothe attenuation of the acoustic excitations. Thesound attenuation, C, measured with the laser (Q =0.078 nm -1 ) and with the synchrotron (Q = 0.11 nm -1 ) agree, within a relative error of 10%, with a Q 2law extrapolated from the BLS data; therefore, thedynamic regime persists at least up to Q= 0.11 nm -1 ,indicating anharmonicity as a likely mechanism. Thelatter, should saturate around frequencies of theorder of 100 GHz. The sound absorption coefficientfor exchanged momenta Q > 0.11 nm_1 is expectedto depart from the Q2 dependence. Experiments in awider range of exchanged Q are in progress.References[1] G. Baldi et al., J. Non-Cryst. Sol. 351, 1919(2005).Authors:G. Baldi(a), S. Caponi (a), L. Comez (c), S. Di Fonzo(b), D. Fioretto (c), A. Fontana (a), A. Gessini (b), C.Masciovecchio (b), M. Montagna (a), G. Ruocco (d),S.C. Santucci (b), G. Viliani (a) - (a) Dipartimentodi Fisica and INFM-CRS Soft, Universita` di Trento,Trento, Italy; (b) Sincrotrone Trieste, Basovizza,Trieste, Italy; (c) Dipartimento di Fisica and INFM-CRS Soft, Universita` di Perugia, Perugia, Italy; (d)Dipartimento di Fisica and INFM-CRS Soft,Universita` di Roma ‘La Sapienza’, Roma, Italy.SOFT Scientific Report 2004-0654

Packing vs. Temperature Effects in PolymersThe pioneering studies of Williams [1] and, morerecently, by Schug et al [2] and Paluch et al [3]pointed out that a deeper insight into the dynamicsof glass-forming liquids and amorphous polymers isgained by the knowledge of the relaxation times as afunction of both temperature and pressure. In fact,the possibility to reach the glassy state by twoalternative paths, i.e., by cooling or compressing,enables a more stringent test of several theories,which usually predict a Vogel–Fulcher kind ofbehavior for the temperature dependence of therelaxation time but different pressure dependencies.We have performed a molecular dynamics simulationFig. 1: The pressure-temperature dependence ofthe segmental relaxation time for a linear polymermodel. The inset shows the pressure dependence ofthe ratio between the isobaric and isochronicexpansivities.of a melt of unentangled polymers [4]. Thetranslational motion, the large-scale and the localreorientation processes of the chains, as well as theirrelations with the so-called ‘‘normal’’ and‘‘segmental’’ dielectric relaxation modes arethoroughly investigated in wide temperature andpressure ranges (Figure 1). The study addresses theissue whether the temperature or the density is adominant control parameter of the dynamics or thetwo quantities give rise to comparable effects. Byexamining the ratio between the isochronic andisobaric expansivities, one finds that the temperatureis dominant when the dynamics is fast. If therelaxation slows down, the fluctuations of the freevolume increase their role and become comparableto those of the thermal energy.The role of packing effects has been alsoinvestigated by addressing the issue of the finitelength of polymer chains which affects both the staticand the relaxation properties of the density of themelt state [5]. These have been investigated bymolecular-dynamics simulations of a Lennard-Jonesmodel with fixed bond length. Under isothermal–isobaric conditions the density increases with themolecular weight. A suitable Voronoi tessellationreveals the extra free volume around the chain endsand shows that it is strongly localized within the firstend monomer (Figure 2). Simple arguments aregiven for interpreting the main changes of themonomer radial distribution function and thecorresponding static structure factor when the chainlength is increased. As to the relaxationaspects of the density, it is found that the structuralrelaxation time increases with the molecular weight,which is interpreted as a signature of the well-knowncorresponding increase of the glass transitiontemperature.References[1] G. Williams, Trans. Faraday Soc. 60, 1548(1964).[2] K. U. Schug, H. E. King, R. Böhmer, J. Chem.Phys. 109, 1472 (1998).[3] M. Paluch, A. Patkowski, E. Fischer, Phys. Rev.Lett. 85, 2140 (2000).[4] A.Barbieri, S.Capaccioli, E.Campani and D.Leporini, J.Chem.Phys., 120, 437 ( 2004 ).[5] A Barbieri, D.Prevosto, M.Lucchesi and DLeporini,J. Phys.: Condens. Matter, 16, 6609 (2004).Fig. 2: The average volume of the Voronoipolyhedra around the monomers located at the nposition along the chain with length M. Note thelarger volume of the polyhedra surrounding thechain-ends ( n = 1).AuthorsA. Barbieri(a), E. Campani(a,b), S. Capaccioli(a,b),D. Leporini(a,b), M.Lucchesi (a,c)(a) Dipartimento di Fisica ‘‘Enrico Fermi,’’ Universita`di Pisa, via F. Buonarroti 2, I-56127 Pisa, Italy (b)CRS-SOFT (c) Dip. Fisica “E. Fermi” Univ. Pisa andCNR-INFM Polylab Largo B. Pontecorvo 3, Pisa.55SOFT Scientific Report 2004-06

Scientific Report – Non Equilibrium Dynamics and ComplexityA Manifestation of the Ostwald Step Rule: The Free-EnergyLandscape of Single-Molecule Polyethylene CrystalsFolded states of chainlike macromolecules includingproteins [1] and crystalline polymers [2] are undercurrent intense study. In spite of the largedifferences between homopolymers and proteins,interesting correspondences between the structuraltransitions of isolated, single homopolymer chainsand the protein folding have been noted by bothnumerical simulations and experiments. One keyissue is if the morphologies of folded states arethermodynamically or kinetically controlled. Kineticfactors are believed to set the growth rate ofpolymer crystals [2] as well as the thickening offolded macromolecules. While this is a safeconclusion for long chains (polymers) , where largeFig. 1: (left) Snapshots of the crystallization of asingle PE chain with N=500 monomers. Note thepresence of initial distinct nucleation sites mergingat later times. (right) Final crystal structure withselected cross-sections.entropic barriers hamper the conformation changesleading to structures which are, e.g., partiallycrystalline, it may be questioned for shorter chains(oligomers) which are less impeded.Extensive molecular-dynamics simulations of thecrystallization process of a single polyethylene chain( PE ) with N=500 monomers have been performed[4-6]. The development of the ordered structure isseen to proceed along different routes involvingeither the global reorganization of the chain or,alternatively, well-separated connected nuclei(Figure 1). No dependence on the thermal historywas observed at the late stages of the crystallization.The folding process involves several intermediateordered metastable states, in strong analogy withthe experiments, and ends up in a well-defined longlivedlamella with ten stems of approximately equallength, arranged into a regular, hexagonal pattern(Figure 1). This behavior may be seen as amanifestation of the Ostwald step rule [3]. Both themetastable states and the long-lived one areevidenced as the local minima and the global one ofthe free-energy landscape (FEL), respectively (Figure2) [4,5]. The study of the microscopic organizationof the lamella evidenced that the two caps are ratherflat, i.e., the loops connecting the stems are short.Interestingly, annealing the chain through thedifferent metastable states leaves the averagenumber of monomers per loop nearly unchanged [6].It is also seen that the chain ends, the so-called cilia,are localized on the surface of the lamella, inagreement with the experiments, and that structuralfluctuations take place on the lamella surface.References[1] M. Gruebele, Annu. Rev. Phys. Chem., 50, 485(1999).[2] G. Ungar, J. Stejny, A. Keller, I. Bidd, and M. C.Whiting, Science 229, 386 (1985).[3] W. Ostwald, Z. Phys. Chem., Stoechiom.Verwandtschaftsl. 22, 289 (1897).[4] L Larini, A Barbieri, D Prevosto, P A Rolla and DLeporini, J. Phys.: Condens. Matter, 17, L199(2005).[5] L Larini, D Leporini, J.Chem.Phys., 123, 144907( 2005 ).[6] L Larini, A Barbieri D Leporini, in press onPhysica A ( doi:10.1016/j.physa.2005.08.048 )Fig. 2: (left) Free-energy landscape ( FEL ) of thePE single-molecule crystals. (right) FEL at differenttemperatures as a function of the largest momentof inertia of the chain. The labels indicate thenumber of stems of the ordered structurescorresponding to the minima.AuthorsA.Barbieri(a), D.Prevosto (a), L.Larini (a,b),D.Leporini (a,b), P.A.Rolla (a)(a) Dipartimento di Fisica ‘‘Enrico Fermi,’’ Universita`di Pisa, via F. Buonarroti 2, I-56127 Pisa, Italy (b)CRS-SOFT (c) Dip. Fisica “E. Fermi” Univ. Pisa andCNR-INFM Polylab Largo B. Pontecorvo 3, Pisa.SOFT Scientific Report 2004-0656

Instrumentations and Methods for NanotechnologyOur interests on instrumentation development,applied to the characterization of mechanical andoptical properties of thin film devices, focusparticularly on two main topics: quartz crystalsmicrobalance and near field optical microscopy.Standard quartz crystal microbalance (QCM) isrouting technique applied to the measure of massdeposited on quartz resonator plate by measuringthe frequency shift. We developed a new QCMdevice with improved time resolution, which allows afull characterization of the mechanical properties(elasticity and viscosity) of the molecular filmdeposited on the electrode. In such instrumentboth the frequency shift and the quality factor Q ofthe resonator are acquired in real time, withresolution of tens of millisecond in time and sub-Hzin frequency. We are currently applying suchtechnique on the study of fast light inducedvariation of viscoelastic properties in photosensitivepolymeric films. In such materials illumination canplay a role equivalent to the temperature[1] withalso the possibility to quench the material optically.With our technique we are able to monitor the fastdynamics taking place during and following thequenching process and aging process as function oftemperature/illumination history.The new QCM devices are applied also to scanningnear field optical microscopy SNOM for an accurateand fast tip sample servo distance control. We alsodeveloped, for SNOM, contrast mechanisms suitablefor molecular axis determination in optical dichroism,birefringence or fluorescence measurements onnanoscale with applications on nanowriting inpolymeric liquid crystals [2].Currently developed technique of the formation ofnanocapsules had attracted a great attention ofresearch groups due to its obvious applicationperspectives. The technique is based on the selfassemblingof polymeric shells on the spherical (orother shape) precursors by means of electrostaticinteractions or by control-precipitation method.When the shell is formed, it was proven to bepossible to remove the precursor varying thecomposition of the solvent (in the most of cases – pHvariation resulted in the solubility of the precursornuclei). Thus, nanocapsules are formed. Animportant feature of these capsules is the smartnature of the shell changing its properties as aresponse of the environmental condition variations.Several applications, such as biosensors, magneticmedia, etc., demand patterned organization of layersof capsules on solid surfaces. We have developedtwo methods of patterning. The first one is based onthe electron beam treatment of capsule layers,deposited by solution casting on solid surfaces [3].Optical microscopy image of resulting patternedlayer, composed by two different types of capsules(hollow capsules and those with gold in the core) isshown in Fig. The method was applied for theformation of layers of magnetic capsules [4].Second method implies self-assembling of capsuleaggregates on the specially prepared solid surfaceswith difference in the hydrophilic/hydrophobicproperties [5]. During assembly, capsules attachthemselves onto hydrophilic areas of the support. Inthe case of hydrophobic coatings with differentdegree of hydrophobicity, capsules form rings on thesurface.References[1] P. Camorani, M.P. Fontana Phys. Rev. E 73,011703 (2006) L. Cristofolini, M.P. Fontana -Philosophical Magazine B84, 1537, (2004). L.Cristofolini, M.P. Fontana T. Berzina, P. Camorani -Mol. Cryst. Liq. Cryst. 398, 11 (2003).[2] P. Camorani, L. Cristofolini , G. Galli, M. P.Fontana Mol. Crystal Liq. Crystal. 375, (2002) 175-184 and P.Camorani, M.Labardi , M. Allegrini - Mol.Crystal Liq. Crystal. 372, (2001) 365-372[3] T. Berzina, S. Erokhina, D. Shchukin, G.Sukhorukov, and V. Erokhin, Macromolecules, 36,6493 (2003).[4] S. Erokhina, T. Berzina, L. Cristofolini, D.Shchukin, G. Sukhorukov, L. Musa, V. Erokhin, andM.P. Fontana, J. Magnetism Magn. Mater., 272-276,1353 (2004).[5] V. Troitsky, T. Berzina, D. Shchukin, G.Sukhorukov, V. Erokhin, and M.P. Fontana, Colloidsand Surfaces A, 245, 163 (2004).Fig. 1. Two-step electron beam patterning of layer ofhollow and gold containing nano-engineeredpolymeric capsules.AuthorsT. Berzina, P. Camorani, L. Cristofolini, S. Erokhina,V. Erokhin, and M.P. FontanaUniversity of Parma and CRS SOFT CNR-INFM.57SOFT Scientific Report 2004-06

Scientific Report – Non Equilibrium Dynamics and ComplexityThe Molecular Mechanism of Muscle ContractionThe cells of the striated muscle, called fibres, areconstituted by ca 2 µm long elementary units, thesarcomeres, that repeat along the axis of the fibre(Fig. 1). In each half-sarcomere, thick (myosincontaining)filaments originating from the M line atthe centre of the sarcomere partially overlap withthin (actin-containing) filaments originating from theZ line bounding the sarcomere. During musclecontraction the generation of the force that pulls theactin filament towards the centre of the sarcomere isdue to a structural working stroke in the globularhead of the myosin cross-linking the myosin and theactin filaments. The work produced is accounted forby the hydrolysis of ATP on the catalytic site of themyosin head. Despite the mass of information frommechanical, biochemical and energetic studies thegap between cellular and molecular levels ofdescription of the myosin motor remains large.Protein crystallography has provided a model of themyosin working stroke with atomic resolution.However, the function of myosin in situ depends onthe interaction between conformational changes inthe motor protein and external force or motion, andthis cannot be reproduced in crystallographic studies.In isolated intact cells from frog muscle, myosinmotors can be synchronised by length or force stepscontrolled at half-sarcomere level and the relatedstructural changes can be recorded with timeresolvedsmall angle X-ray diffraction (SAXS) usingsynchrotron light. The brightest axial reflection of thediffraction pattern from single fibres, called M3,originates from the 14.5 nm axial repeat of themyosin motors along the filament axis (Fig. 1) and issensitive to axial movements of the myosin headsduring the working stroke [1].A breakthrough for SAXS technique has been thefinding that with the spatial resolution of 3rdgeneration synchrotrons (ESRF, Grenoble, France;APS, Argonne, IL, USA) it is possible to record thefringes generated in the M3 reflection by theinterference between the two arrays of myosinmotors in each sarcomere [2]. Due to the bipolararrangement of the myosin motors in the two halvesof the sarcomere, the interference effect provides Åscale direct measure of the axial movement of themotors [3]. The changes in interference fringes ofthe M3 reflection, following stepwise reduction of theZ-line14.5 nmMyosin filamentMyosinheadsM-lineActin filamentFig. 1: Structural model of muscle contraction atthe level of the sarcomere. Arrangement of the actinand myosin molecules in the muscle sarcomere.Grey, actin filament; blue, myosin filament; red;myosin heads. Sarcomere shortening (transitionfrom upper to lower panel) is associated with tiltingof myosin heads so that actin filaments are pulledtoward the M-line.1.00.50.00-5-10-15-20abForce ( T 0 units)L 0 1L 2s 2L 2e L 33Length change (nm hs -1 )0 5 10 15 20Time (ms)0.066 0.068 0.070 0.072Fig. 2: Mechanical and structural responses to aload step. (a) Load step normalised by theisometric force T 0. (b) Length change in nm perhalf-sarcomere; numbers next to the recordindicate the various phases of the shortening: theelastic change in strain (1); the early sliding due tothe synchronised working stroke in the myosinheads (2); the pause (3) and steady sliding (4) dueto detachment/attachment of myosin heads fartheralong the actin filament. (c) Axial intensitydistribution in the region of the M3 reflection at theperiods corresponding to the X-ray exposure timesshown in (b): brown L 0, isometric contraction;orange L 2s, start of phase 2; pink L 2e, end of phase2; blue L 3, end of phase 3. Myosin heads movetowards the centre of the sarcomere during phase 2and detach from actin during phase 3.force from the isometric value with a force feedbackcontrol, showed that the myosin working stroke is 11nm and takes

Time Resolved X-rays Scattering from Disordered SystemsThe tehnique on ID09B beamline at the ESRF.This technique allows to probe the X-rays scatteringintensity changes following a perturbation induced inthe sample by a laser pulse. The time resolution isgiven by the pulsed structure of SynchrotronRadiation: the pulse duration is determined by theelectrons bunch length and at the present timecorresponds to 100 ps. So the technique looks likean optical pump and probe experiment the uniquething being the microscopic structural informationprovided by an X-rays pulse as probe signal. Theexperiment is performed locking the laser phase onthe electrons bunch frequency in the ring. Themaximum repetition rate of the laser is much slowerrespect to the X-rays emission then a rotativechopper allows to reject the pulses to match the1Khz laser emission (or slower if needed). The timedelay is finely tuned by means of a fast timing diodefrom the value imposed by the repetition rate up tothe 100ps X-pulse resolution. For a fixed time delaythousands of pulses are collected on a CCD giving ascattering image: this is usually subtracted from ano-laser one to get a difference pattern which couldbetter give the microscopic structural information. Asthe detector has not time resolution the sample mustbe replaced at each pulse: a standard experiments isthen usually performed making the liquid flowing ina jet in order to recover the scattering volume eachmillisecond. The optic pump setup now consists of acryogenically cooled 13 passes Dragon amplifierwhich make available 100 femtosecond pulses at800 nm wavelength with an energy up to 2.5 mJ perpulse; a TOPAS system is also available to tune thepump in a wide range of wavelengths.Probing photochemical reactions in solutions.One of the most important application of thetechnique has been the observation of the laserinduced reactions in photoactive molecules. Thedifferent steps of the excited molecule reactionproduce a structural information that can bedetected in the difference pattern: ref [1] gives anexhaustive example of a typical application inphotochemistry. In this kind of the experiments theanalysis has to account for the global changes of thesolution due to the solvent rearrangement aroundthe solute and the heat released: numericalsimulations and laser heating [2] experiments onthe solvent play a crucial role to extract the soluteinformation. Once this information is achieved onecan develop a sort of molecular movie providingunique information on the structures involved in thereactions pattern and their lifetime.Impulsive Infrared Heating in simple liquids.The exigency of extracting solute information inphotoreactions dynamics turned our attention on thedynamic following an impulsive heating in a simpleliquid. An infrared pulse can be used toinstantaneously release heat in the sample producingan initial temperature and pressure jump at constantvolume which first induce a pressure wave to relax tomechanical equilibrium and then equilibrate thetemperature on larger timescales. Thishydrodynamics can be observed from a microscopicpoint of view by this technique allowing toinvestigate how the hydrodynamic theory accountsfor the temporal evolution of the signal on smalllength-scales. Typical difference patterns at differenttime delays are reported for methanol in the figurebelow: the increment of the signal around 10nsmarks the expansion dynamics. Moreover severalliquids cross a metastable negative pressure stateduring the expansion dynamics following the heating(corresponding to the peak region in the figure): thisstate together with cavitations effects can bestudied in his structural and dynamical features.Impulsive infrared heating in glassformers. Onthe way of using this technique as a sort of thermalstimulated scattering with a microscopic probe andtaking advantage of the extremely large timescaleswindow available our attention is now moving to thestudy of complex liquids and glasses: in this class ofsystems the presence of the slow structuralrelaxations dynamics allows to observe the structuralchanges before the thermodynamic equilibrium isreached. This project is still work in progress:developments of the sample environment have beennecessary to extend the technique to not flowingsystems and to implement a thermal control to heatand cryogenically cool the sample. A rotative cellsystem has been tested and is now available toreplace the scattering volume at the repetition rateneeded. The application of this technique to glassesmight offer a new tool for the study of the slowdynamics in this class of complex systems from amicroscopic point of view. Further developments inpotentially interesting directions for the SOFTcommunity might include polymers studies andcolloidal systems also considering that time resolvedsmall angle experiments have already beensuccessfully performed [3].References[1]H.Ihee et al., Science 309, 1223 (2005).[2] M.Cammarata et al., JCP 124, 124504 (2006).[3] A.Plech et al. CPL 401, 565 (2005).Authors:M. Cammarata(a), M. Lorusso(a), Q. Kong(a), E.Pontecorvo(b), G. Ruocco(b), F.Sette(a), M.Wulff (a).(a) ESRF, Grenoble, France.(b) Dipartimento di Fisica, Universita' di Roma 'LaSapienza' and CRS SOFT-INFM-CNR, Roma, Italy.59SOFT Scientific Report 2004-06

Scientific Report – Non Equilibrium Dynamics and ComplexityGlass Transition in Photosensitive PolymersOptical pumping of the isomerization transition inpolymeric systems containing the azobenzene moietyhas received much attention in recent years, mainlybecause of applications to optical writing, potentiallydown to the nanoscale [1]. To this end, however,much fundamental study is still necessary, due tothe complexity of the systems, which feature a richphenomenology of relevance to phase transitions inliquid crystals, the glass transition, dewettingphenomena[2], the anomalous diffusional andvibrational dynamics in spatially heterogeneoussystems, and to the well known anomalies in the lowfrequency vibrational density of states (VDOS)ofglass formers. A link is generally found between thedynamical fragility m, and the Boson Peak, which inturn seems in many cases to be related to the localstructure of the glass. However it is still not clearwhat is the cause of the vibrational anomalies, oreven if there is only one general cause. It is hopedthat the study of photosensitive polymers could helpin solving this problem, in particular due to thepossibility of inducing or modifying morphology downto the nanoscale.As part of this general program, we have describedseveral effects on the macroscopic scale: changes inrheological properties probed by opticalmeasurements [3] and by direct measurements onLangmuir monolayers [4] and in bulk [5], leading tothe possibility of fast optical quenching of thematerial; relaxation times are sensitive to theapproach of the glass transition [6]. In spite of theextent of experimental work and modeling, it is stillnot clear what the actual connection is between themicroscopic phenomena related to azobenzeneisomerization and the changes in the macroscopicproperties of the system. We have studied the lowfrequency dynamics on the same material by acombination of neutron scattering techniques,showing that while at low energy, low momentum,we had a standard picture for a polymer but nophotoinduced effect, in the intermediate region ofEnergy (meV)1412108642Fig. 1.Hg OFFHg ON00 5 10 15Exchange momentum, Q (nm -1 )the BP a reduction of the v-DOS was observed uponUV illumination [7]. Therefore basic purpose of ourmost recent activity is to connect the nanoscalesingle molecule optically induced conformationalchanges of the azobenzene side chain to the abovediscussed macroscopic effects of fluidification andspatial homogenization, through the study of theeventual photoinduced changes in the low frequencyvibrational dynamics as probed by differenttechniques.As an example in the following we discuss the resultsrecently obtained by Inelastic X-Ray scattering onthe beamline ID16 of ESRF in dark and under UVillumination, with the incoming X-ray beam focuseddown to 30X100 µm 2 . The measured Q rangecovered up to the first sharp maximum in the staticstructure factor S(Q). IXS data were analyzed with astandard Damped Harmonic Oscillator model plus apurely elastic component. In the figure we show thedispersion curves as measured at T=200K in darkand under UV photoperturbation.The photoperturbation mostly affects the dispersioncurve in the high Q region, while the low Q, longrange structure of the polymer remains unaltered.The photoinduced difference becomes maximumaround 15 nm -1 , which corresponds to the first sharpmaximum in the static structure factor. This suggeststhat photoisomerization, a process that is located onthe scale of the single molecule, affects macroscopicproperties such as viscosity, via the softening of aborder zone mode which is likely to have at leastsome transverse (or localized) character. These ideashave received preliminary confirmation from lowfrequency Raman data, and a preliminary report hasbeen submitted for pubblication [8].References[1] P. Camorani, M. Labardi, M. Allegrini - Mol. Cryst.Liq. Cryst. 372, 365-372 (2001).[2] L. Cristofolini, S. Arisi, M. P. Fontana - Phys.Rev. Letters 85, 4912 (2000). L. Cristofolini, M.P.Fontana T. Berzina, P. Camorani - Mol. Cryst. Liq.Cryst. 398, 11 (2003).[3] Sanchez,-C.; Alcala,-R.; Hvilsted,-S.;Ramanujam,-P.-S. Appl.Phys.Lett. 77, 1440 (2000)P. Camorani, PhD Thesis, Univ. of Parma (2004).[4] L. Cristofolini, M.P. Fontana - PhilosophicalMagazine B 84, 1537, (2004).[5] P. Camorani, L. Cristofolini, G. Galli, M. P.Fontana - Mol. Cryst. Liq. Cryst. 375, 175 (2002).[6] L. Cristofolini, P. Cicuta, M.P. Fontana- J.Physics: Condensed Matter, 15, S1031 (2003).[7] L. Cristofolini, M.P. Fontana, M. Laus B. Frick -Phys. Rev. E, 64, 061803 (2001)[8] L. Cristofolini et al. Submitted for pubblicationAuthorsP.Camorani, L.Cristofolini, M.P.Fontana, E.PontecorvoUniversity of Parma CRS SOFT CNR-INFM.SOFT Scientific Report 2004-0660

Polarization Fluctuation and Dissipation in Out of EquilibriumSystemsSystems characterized by slow dynamics can bedriven to out of thermodynamic equilibrium states bymeans of a rapid change of appropriate externalvariables, for instance a temperature jump taking aliquid down to a glassy state. After such treatment,the system tends to relax to the thermodynamicequilibrium state, and the properties (dynamic,thermodynamic, mechanical) of the system dependon t w, the time elapsed after the achievement of theout of equilibrium state [1]. In an out-of-equilibriumsystem the response to a small externalperturbation, especially at long time, is not longerrelated, via the temperature of the thermal bath, tothe spontaneous fluctuations of the variable undertest, as predicted by the fluctuation-dissipationtheorem (FDT) [2], since both the fluctuations andFig. 1. (a) Normal probability plot and (b) voltagevs. time series at tw=30 min. after a quenching at278 K. (c) and (d) show the same plots atequilibrium after a slow cooling at 278 K. Crossesare the experimental values. Straight lines in (a)and (c) show the expected values for a Gaussiandistribution. Voltage values are amplified by the gainof the amplifier (factor 1800).the response depend on the thermal history of thesystem. In such situation the temperature of thesystem is not well defined any more, and it cannotbe used as an unique parameter able to describe thedynamic behaviour. Recently, the dynamics of outof-equilibriumsystems has been tentativelydescribed by introducing a temperature (fictive), T eff,defined by a generalization of the FDT [2]. Such aparameter should take into account the thermalhistory in the new thermodynamic description of outof-equilibriumsystems. Apart from the number ofsimulation works verifying the violation of the FDT inout-of-equilibrium systems, experimental worksconcerning glassy systems are almost missing. Wedeveloped an apparatus to measure simultaneouslythe complex permittivity (susceptibility) by dielectricspectroscopy and the polarization fluctuations(correlation function) observed via the voltage noise,produced by a capacitor cell filled with the glassformerunder test [3]. We performed measurementson an epoxy organic glass former both above andbelow the glass transition temperature. Thepolarization noise followed the predictions of the FDTwhen the material is at the thermodynamicequilibrium state or weakly out. In the out-ofequilibriumstate an intense polarization noise wasdetected, much more than that measured atequilibrium (Fig. (1b) and (1d)). A non-Gaussiandistribution of the probability density function of thepolarization fluctuations was observed immediatelyafter a rapid quenching of the sample below theglass transition temperature (Fig (1a) and (1c)). Thewidth of the distribution reduced during aging and itsshape tended towards a Gaussian distribution as theequilibrium state was approached [3]. T eff wascalculated for the dynamics properties in threedifferent frequency regions and for different valuesof the temperature of the thermal bath, T b (Fig. (2))[3]: (a) at the highest frequency (20 Hz) the FDTrelation holds above and below T g with T eff=T b (seeinset); (b) at the lowest frequency (0.2 Hz) a strongdeviation from the FDT prediction occurs just fewdegrees above T g and T eff reaches huge values (>105K) at lower temperatures; (c) at 2 Hz the deviationfrom FDT occurs below T g and the values of T eff areintermediate compared to the cases (a) and (b).References[1] Statistical Physics II, R. Kubo, M.Toda andN.Hashitsume (Springer Ser. on Solid-State Sci.,vol.31 Berlin, Heidelberg, 1992).[2] L.F.Cugliandolo, J.Kurchan, L.Peliti, Phys.Rev.E.55, 3898 (1997).[3] M. Lucchesi, A. Dominjon, S. Capaccioli, D.Prevosto, P.A. Rolla accepted on Journal of Non-Crystallyne Solids.Fig. 2. Effective temperature T eff calculated at threedifferent frequencies. Lines are guide for the eyes.Inset shows an enlarged view for the range aboveTg, straight line represents T eff=T.AuthorsS. Capaccioli (a), M. Lucchesi (b,c), A. Dominjon (b),D. Prevosto (b,c), P. Rolla (b,c)(a) CNR-INFM, CRS-Soft and Dip. Fisica “E. Fermi”Univ. Pisa. (b) Dip. Fisica “E. Fermi” Univ. Pisa and(c) CNR-INFM Polylab Largo B. Pontecorvo 3, Pisa.61SOFT Scientific Report 2004-06

Scientific Report – Non Equilibrium Dynamics and ComplexityRelation Between Thermodynamic and Dynamic Properties inGlass FormersThe investigation of the glass transition phenomenonis a central topic in the field of amorphous condensedmatter. In fact, the understanding of the glasstransition phenomenon can improve the knowledgeof materials used in the fields of pharmaceutical andmedical applications, food-packaging, plasticelectronics, and more generally amorphousmaterials. Several investigations performed bystudying dynamic properties of glass formerssystems varying pressure, P, and temperature, T,revealed that reduction of thermal energy and ofdensity play an equally important role in thevitrification process [1]. The Adam and Gibbs (AG)theory of glass transition includes both thesecontributions since it relates the increase ofstructural relaxation time, τ, occurring onapproaching the glass transition, to the reduction ofconfigurational entropy, S c, by [2],⎛ CT,P)= τ exp⎜⎝ TSc⎞⎟⎠AGτ (0(1)log(1/τ max[s -1 ])log(1/τ max[s -1 ])log(1/τ max[s -1 ])4.0TPC3.53.02.52.01.51.00.84 0.86 0.88 0.90 0.92 0.94 0.96 0.98 1.00 1.02 1.04543265432101.00 1.05 1.10 1.15 1.20 1.25 1.30 1.35 1.401.5x10 -3 2.0x10 -3 2.5x10 -3 3.0x10 -3 3.5x10 -3 4.0x10 -310 4 X [J -1 mol]OTPPMMAFig. 1: Logarithmic of the inverse of relaxation timelog(1/τ max) (symbols) as a function of X∝(TS C) -1 , forTPC (0.1-69 MPa), OTP (0.1-79 MPa), and PMMA(0.1-200 MPa). Different symbols for the samesystem correspond to different values of pressure.where τ 0 the value of τ in the limit of infinite (TS c),and C AG assumed as a constant. Since the AG theoryincludes the contributions of the thermal energy andof the density, it appears as a suitable theory for theinterpretation of the glass transition phenomenon.Unfortunately, the configurational entropy is not aquantity that can be experimentally determined, andthis shortage represented a big limitation in theapplicability of this theory.Recently, we proposed a phenomenological model toestimate the configurational entropy as a function oftemperature and pressure, basing on calorimetricand thermal expansion data [4]. By this expressionof S c we extended the use of the AG Eq. (1), whichat the beginning was used to consider temperaturevariations, to take into account also the effect ofpressure on the dynamic properties of the materials.The relation we proposed relates thermodynamicquantities, such as molecular volume and heatcapacity, to dynamic ones (relaxation dynamics).The proposed equation, tested on systems wherethermodynamics and dynamics data were available,revealed to relate such quantities. In Fig. 1 a fewexamples of the obtained results are shown for threedifferent materials: o-terphenyl (OTP),triphenylchloromethane (TPC) and poly (methylmethacrylate) (PMMA). The logarithm of the inverseof relaxation time, measured for different values oftemperature and pressure, is plotted as a function ofa quantity inversely proportional to S c. Each symbolrefers to a different value of pressure. For eachsystem all the data can be reproduced by a singlelinear equation. Due to the good quantitativeagreement with experimental data, the model can beused to predict the dynamic properties at highpressure when few quantities (isothermalcompressibility, ambient temperature calorimetriccurve, relaxation time at ambient pressure) areknown.References[1] M. L. Ferrer, et al. J.Chem.Phys. 109, 8010(1998); C.M. Roland, R. Casalini Macromol. 36, 1361(2003).[2] G.Adam, J.H.Gibbs J.Chem.Phys. 28,139 (1965).[3] D. Prevosto, S. Capaccioli, R. Casalini, M.Lucchesi, P.A. Rolla Phys. Rev. B 174202, 67(2003) ; D. Prevosto, S. Capaccioli, M. Lucchesi, D.Leporini, P.A. Rolla, J. Phys.: Condens. Matter 16,6597 (2004); S. Capaccioli, M. Lucchesi, D. Prevosto,R. Casalini, P.A. Rolla, Philosophical Magazine B, 84,1513-1519, (2004)Authors:S. Capaccioli (a), D. Prevosto (b), M. Lucchesi (b), P.Rolla (b)(a) CNR-INFM, CRS-Soft and Dip. Fisica “E. Fermi”Univ. Pisa. (b) Dip. Fisica “E. Fermi” Univ. Pisa andCNR-INFM Polylab Largo B. Pontecorvo 3, Pisa.SOFT Scientific Report 2004-0662

High-frequency dynamics of v-GeO 2The effect of disorder on the density fluctuations is atopic with so many unsolved aspects that measuringthe dynamics at THz frequencies in simple glassesremains a class of demanding experiments. Severalattempts have been made to experimentally identifythe nature of the excitations in the mesoscopic region,as well as the origin of the excess of states in thedensity of states (DOS) which gives rise to the BosonPeak (BP). Inelastic x-ray scattering (IXS) experimentsat THz frequency were carried out in several glassesand evidence for the existence of phonon-likeexcitations was found [1,2]. A recent contribution camefrom the observation of two excitations in the currentspectra of v-SiO 2 on IXS data and the persistence ofpropagating sound waves up to Q values close thepseudo-Brillouin-zone edge [2]. The experimentalfindings were complemented by the results of MolecularDynamics Simulations (MD) [3]. This work [4] isdedicated to the investigation of the high frequencydynamics of v-GeO 2 carried out by exploiting four INSspectrometers operated over complementarykinematics ranges with different energy resolutions. Insuch a way, access to a wide kinematics range with aresolution adequate to resolve the inelastic featuresunder investigation was obtained. Brillouin peaks, welldefined and resolved from the tails of the elastic peak,are clearly apparent from the spectra independently ofany model or data treatment. Increasing Q, the peakposition shifts towards higher which reveals, beyondany doubt, the propagating character of this excitation.At low Q, besides the inelastic peak associated to thesound mode, both theoretical and numerical studiespredict a second dispersing excitation in the dynamicresponse function, suggesting the existence of atransverse-like dynamics (Fig. 1).1000 IN1 0.3 Å -1The whole set of the present neutron data in v-GeO 2 isconsistent with the picture of propagating vibrationalexcitations, namely a first mode which shows aremarkable dispersion, beyond which it merges into abroad inelastic bump roughly centred at ∼30 meV, anda second mode characterized by much lower excitationenergies and a much less pronounced dispersion. Weassign a longitudinal acoustic character to the firstmode and a transverse acoustic nature to the secondmode, whose flattening at large Q could contribute tothe excess of vibrational states typical of the high-Q BP.The visibility of a transverse excitation in theintrinsically longitudinal density fluctuation spectra of adisordered system can be justified by the mixingphenomenon: the polarization character of thevibrations, which is well defined at low Q, becomesmore and more ill-defined at larger Q. At highfrequency the transverse dynamics acquires alongitudinal symmetry component, observable by INSmeasurements. To give further ground to the presentinterpretation, we carried out a MD simulation on v-GeO 2 using 680 molecules in a cubic box correspondingto the density ρ=3.6 g cm -3 , interacting through a VanBeest-type potential. Longitudinal and transversecurrent spectra were obtained from the simulations andthey reproduce the vibrational features observed in theexperimental spectra. The dispersion relationsassociated to the different modes are shown in fig 2together with the results of MD. In conclusion we foundclear presence of two well defined peaks with anassociated dispersion, which were assigned to the highfrequency counterpart of the LA and TA modes. Thecomparison between experimental and simulateddispersion curves supported the hypothesis that thequasi-transverse acoustic modes contribute to the BP.60500S(Q, ω) [a.u.]01000 0.5 Å -15001000 IN8 0.65 Å -1500010000-30 -20 -10 0 10 20 305000-30 -20 -10 0 10 20 3080 IN3 0.75 Å -1604020080 2.0 Å -16040200-10 -5 0 5 10ω [meV]0.8 Å -1Fig. 1 Selection of INS spectra of v-GeO 2 at 300 K.Spectra show a well defined high frequency-peakdispersing in q. the low two panels show a lowfrequencyexcitation, masked in the upper spectra.Dashed lines represent the spectrometer resolutions.ω [meV]402000 2 4Q [Å -1 ]Fig. 2. Dispersion relations of v-GeO 2 as resulted fromthe fitting of the neutron data are compared with themain maximum of the simulated L (higher branch) andT (lower branch) current spectra (open triangles). Thedashed lines are the L and T sound velocity.References[1] O. Pilla et al. Phys. Rev. Lett.85, 2136 (2000).[2] B. Ruzicka et al. Phys. Rev. B 69, 100201(2004).[3] O. Pilla et al., J. Phys. Cond. Mat. 16, 8519 (2004).[4] L. E. Bove, Europhys. Lett., 71 (4), 563 (2005).Authors:S. Caponi (a), A. Fontana (a), L. E. Bove (b)(a) Dipartimento di Fisica and INFM-CRS Soft,Università di Trento, Trento, Italy; (b) CRS-SOFT Unitàdi Perugia.63SOFT Scientific Report 2004-06

Scientific Report – Non Equilibrium Dynamics and ComplexityBrillouin visible and ultraviolet light scattering measurementsin v-SiO 2 and silica porous systemsIt is known that a planewave excitation can propagatein a disordered structure only when the wavelength ismuch longer than the scale spanned by microscopicinhomogeneities; as the wavelength shortens, the waveis increasingly distorted and scattered. The question asto the causes of attenuation far from the longwavelength limit, is unlikely to have a single answer,and different mechanisms have been suggested.Depending on the physical origin of the acoustic energydissipation, the attenuation can be stronglytemperature dependent (dynamic) or temperatureindependent (static). In order to clarify the interplaybetween different mechanisms, is necessary toinvestigate as thoroughly as possible, besides thetemperature evolution, also the frequency evolution ofthe acoustic attenuation.Brillouin Light Scattering (BLS) and Inelastic X-RayScattering (IXS) experiments do not cover the wholefrequency and q range from GHz to THz, andinvestigations within the frequency gap which separatesthese techniques could be useful to discriminatebetween the different hypotheses.With this purpose, thanks to a newly availablespectrometer HIRESUV, Ultraviolet Brillouin lightscattering(BUVS) experiments are possible in anunexplored frequency region. We have investigated twoprototype systems v-SiO 2 and silica porous systems.For v-SiO 2, considered as the prototype strong glass,the comparison of the new data with those obtained byIXS and BLS indicates [1]:1) the existence of a crossover among differentattenuation mechanisms: from a dynamic onecharacteristic of low frequency region to a static one,which dominates in the high frequency regime.2) necessarily somewhere in the intermediate range,the acoustic attenuation have to grow faster thanquadratically with q (see fig.1).As regard porous systems, investigating the attenuationof phonons with different wavelength in homogeneoussystems, is equivalent to investigate the attenuation ata given wavelength varying the size of the microscopicinhomogeneities. We have studied samples withdensities between 500 and 2200 kg/m 3 , as aΓ(GHz)1000 BUVS T=300KIXS T=1050KIXS T=300K100 POT T=300KBLS T=300K1010.10.01 0.1 1Q(nm -1 )Fig. 1 Log-log plot of Brillouin widths as a function ofthe exchanged wave vector q, obtained at roomtemperature by BLS, BUVS, IXS, POT. The dashedlines, indicating the q 2 law, are guides for the eye.consequence of a controlled sintering procedure leadingto modifications of their “texture” and of the networkconnectivity. A dynamic to static transition in theattenuation has been found by Brillouin light scatteringmeasurements (see Fig.2) [2]. The static or dynamicalorigin of the attenuation is ascribed to the interplaybetween the mean pore sizes of the samples and theprobe wavelength. This hypothesis is confirmed by thebehaviour of attenuation investigated at twowavelength (see insets of fig.2). A crossover length a*related to the pore size has been determined. For themean pore size smaller than a* the largest contributionto the absorption comes from the attenuation due todynamic mechanisms, such as relaxation processes andanharmonic coupling. For pore size larger than a*, therapidly growing sound attenuation can be attributed tothe disorder due to inhomogeneities produced by pores.HWHM (GHz)0.10.01Densified xerogelΓ (MHz)Γ (MHz)3002001000500400300200λ= 514.5 nmα-quarz0 5 10 15a * (UV)a * (BLS)λ= 266.0 nm0 5 10 15L1E-3p(nm)0 200 400 600 800 1000 1200Temperature (K)aerogel1xerogel1v-SiO 2Fig. 2.Temperature behaviours of the half width halfmaximum of the Brillouin peak in systems withgrooving pore size. In the inset HWHMs of visible andultraviolet Brillouin peaks versus the mean pore size.References[1] P.Benassi et al. Phys. Rev. B 71, 172201 (2005).[2] S. Caponi et al. Phys. Rev. B 70, 214204 (2004).[3] S. Caponi Phil. Mag., 84, Nos.13–16,1423 (2004).Authors:S. Caponi (a), P. Benassi (b) R. Eramo (c), A. Fontana(a), A. Giugni (b), M. Nardone (b), M. Sampoli (d), andG. Viliani (a)-(a) Dipartimento di Fisica and INFM-CRSSoft, Universita` di Trento, Italy; (b) Dipartimento diFisica, and INFM-CRS Soft, Università dell’Aquila, Italy;(c) Dipartimento di Fisica and LENS and INFM-CRS Soft,Università di Firenze, Italy; (d) Dipartimento diEnergetica and INFM-CRS Soft, Università di Firenze,ItalySOFT Scientific Report 2004-0664

Microscopic Dynamics in Liquid MetalsLiquid metals are an outstanding example of systemscombining great relevance in both industrialapplications and basic science. On the one hand theyfind broad technological application ranging from theproduction of industrial coatings (walls of refinerycoker, drill pipe for oil search) to medical equipments(reconstructive devices, surgical blades) or highperformance sporting goods. Most metallic materials,indeed, need to be refined in the molten state beforebeing manufactured. On the other hand liquidmetals, in particular the monoatomic ones, havebeen recognized since long to be the prototype ofsimple liquids, in the sense that they encompassmost of the physical properties of real fluids withoutthe complications which may be present in aparticular system Inelastic.Neutron Scattering played a major role since thedevelopment of neutron facilities in the sixties. Thelast ten years, however, saw the development ofthird generation radiation sources, which opened thepossibility of performing Inelastic Scattering with Xrays, thus disclosing previously unaccessible energymomentumregions. The purely coherent response ofX-rays, moreover, combined with the mixedcoherent/incoherent response typical of neutronscattering, provides enormous potentialities todisentangle aspects related to the collectivity ofmotion from the single particle dynamics.S(Q,ω) [a.u.]B280240200160120804001501209060300Na-K44/56KNaQ = 0.29 Q Max-4 -3 -2 -1 0 1 2 3 4E / E 0180150120Collecting data on a sizeable library of system, bymeans of new X-ray and Neutron experiment andexisting literature, we identified the commonfeatures of microscopic dynamics at differentwavelengths and frequencies, from a stronglycorrelated regime to the single particle domainthrough the intermediate, hard-sphere like, kineticregime.9060300In liquid alloys a similar scenario holds. In particularthe generalized hydrodynamic theory correctlydescribes for the spectral lineshapes. An additionalrelaxation process, however, related to theconcentration fluctuation, has to be accounted forbeside the usual two-step relaxation process rulingthe acoustic properties in monoatomic fluids.References[1] T. Scopigno, G. Ruocco and F. Sette, The Reviewof Modern Physics 77, 881 (2005).[2] T. Scopigno, R. Di Leonardo, L. Comez, A.Q.R.Baron, D. Fioretto and G. Ruocco, Physical ReviewLetters 94, 155301, (2005).In the last few years, we investigated the highfrequency dynamics in several simple liquids,comprising monoatomic fluids and binary mixtures.While the long wavelength regime is well understoodin terms of ordinary hydrodynamics, the atomicmotion at lengthscales comparable to the interatomicdistance is still debated.AuthorsS. Cazzato (a,b), G. Ruocco (a,b), T. Scopigno (b).(a) Dipartimento di Fisica Universita’ Roma ‘’LaSapienza’’, 00185 Roma, Italy.(b) CRS SOFT-INFM-CNR, Roma, Italy65SOFT Scientific Report 2004-06

Scientific Report – Non Equilibrium Dynamics and ComplexityNon-Ergodicity in Locally Ordered SystemsThe current interest in studying the structurallyarrested states of matter is based on searching for abasic mechanism underlying the onset of theparticle-blocking of motion, common to differentclasses of systems.Suppose a tagged particle is trapped in a transientcage made by its nearest neighbours, which arecaged themselves. With decreasing temperature, theparticle becomes progressively more confined in itscage and partakes correlated collisions.Subsequent diffusion out of the cage needs acooperative rearrangement of many particles andprovides long-range transport motion, which slowsdown drastically as the temperature is lowered. Thiscage effect mechanism can be regarded as themicroscopic origin of the eventual structural arrest ofa simple liquid that occurs at the glass-transition. Inmore complex systems like associated and covalentliquids, the ubiquitous class of liquids including waterand silica, the cage effect manifests a differentnature since molecules are blocked in energeticcages of hydrogen or covalent bonds, and bondbreaking and formation is needed for diffusion tooccur. This is why finding a unique paradigm toexplain the particle dynamics and the particle cagingof different classes of systems actually constitutes abig challenge for condensed matter physics.f Qf Q0.90.80.70.6Q=2 nm -10.50.951.00.90.80.70.95Q=4 nm -10.900.900.850.850.80Q=7 nm -1Q=10 nm -10.750.8050 100 150 200 250 300 50 100 150 200 250 300T(K)T(K)Fig. 1: Temperature dependence of the nonergodicityfactor f Q of m-toluidine for different Q-values. The solid lines are the best fits obtainedusing the square-root function predicted by theMCT.Intensity64200 2 4 6 8 10 12 14 16 18Q (nm -1 )Fig. 2 X-ray diffraction pattern (left axis) of liquidm-toluidine at ambient temperature taken from Ref.[2], compared with the parameter f Q c (right axis)obtained from the fit of the experimental f Q(T) data(open circles); full squares indicate the values of f Qat T=263 K - a temperature in the plateau region off Q(T) - for all the available Qs.1.00.80.6f QcOriginally, the mode coupling theory (MCT) wasproposed as an approximation approach for the cageeffect in liquids [1]. In its simplest version, thederived equations of motion for the densityfluctuationslead to a bifurcation of the long-timelimit of the density correlators, the so-called nonergodicity factor f Q, if a control parameter liketemperature crosses a critical value, T c. Within MCT,specific predictions are postulated for thetemperature and wave-vector dependence of f(Q,T):i) A square-root temperature behaviour below T c,i.e., f Q(T)=f c Q +h Q(1-T/T c) 1/2 , where f cQ is the criticalnon-ergodicity parameter and h Q the criticalamplitude at a fixed wavevector Q; ii) A Q-cdependence of f Q and of h Q that follows theoscillations of the static structure factor S(Q).While a large number of experimental and theoreticalworks have verified the MCT predictions in Van-der-Waals molecular liquids, few investigations havebeen devoted to associated and covalent liquids, andthe results are often not exhaustive. In these liquidsthe local order extends over several neighboringmolecules and reflects on a nontrivial Q behavior inthe low-Q region of the static structure factor, S(Q).We investigated a molecular system, m-toluidine,which is characterized by a spatial organization ofthe molecules induced by hydrogen bonds extendingover several molecular diameters and giving rise tonanometer size clusters [2]. The non-ergodicityfactor of supercooled and glassy m-toluidine hasbeen measured, through IXS experiments (beam lineID16-ESRF), in the mesoscopic Q range between 1and 10 nm -1 , around the prepeak in the staticstructure factor related to the local order (Q pp=5nm -1 ). We proved that the basic predictions of MCTabout the non-ergodicity factor hold in m-toluidine(see Figure 1 and Figure 2), providing experimentalevidence that the signature of the ergodic to nonergodictransition, valid for simple liquids, lives on inclustering systems [3]. Our findings suggest that theinitial stage of the cooperative rearrangements,where the cage effect dominates the moleculardynamics, exhibits a universal character, common tosimple liquids and liquids with a local order. Thisconcept is not so obvious, because it places on thesame level the structural arrest in simple and inlocally ordered liquids, though the cage formation iscontrolled by different mechanisms.References[1] W. Götze and L. Sjögren, Rep. Prog. Phys. 55,241 (1992).[2] D. Morineau et al., Europhys. Lett. 43, 195(1998); M. Descamps et al., Prog. Theor. Phys.Suppl. 126, 207 (1997).[3] L. Comez et al., Phys. Rev. Lett. 94, 155702(2005).Authors:L. Comez (a), S. Corezzi (b), G. Monaco (c), R.Verbeni (c), and D. Fioretto (a).(a) CRS-SOFT and Dipartimento di Fisica, Universitàdi Perugia, Perugia (Italy), (b) CRS-SOFT andDipartimento di Fisica, Università di Roma LaSapienza, Roma (Italy), (c) ESRF, Grenoble (France).SOFT Scientific Report 2004-0666

Nonlinear Optics in Soft-MatterLight propagation in soft-matter such as colloidalsystems can be affected via a feedback mechanismby light induced structural changes, owing to theirhigh responsivity to external stimuli. In spite of suchattractive feature and the low powers needed toobserve nonlinear phenomena, the optical nonlinearresponse of soft matter was generally overlookedwith the exception of metal colloids (whosenonlinearity is mediated by surface polaritons) andliquid crystals that display a giant reorientationalnonlinearity. We have considered the case of acolloidal suspension of dielectric particles dispersedin a solvent, characterized by tunable interactionsthat can be responsible for long range correlationsand even phase transitions such as gelation. The roleof the structure of these materials in nonlinearoptical processes is essentially unexplored.Large scale ordered structures can indeed affectorientational, electrostrictive, and thermophoreticmechanisms. For isotropic particles and negligiblethermal gradients due to light absorption, theleading optical nonlinear mechanism is expected tobe electrostriction: the particles are subject to forcesinduced by light intensity gradients, thus moving inthe region with higher or lower intensity dependingon the difference between their refractive index andthat of the host medium. In both cases, the opticalbeam experiences self-focusing, a process which hasbeen described by a local Kerr law or intensitydependentrefractive index variation. Recently,however, we have shown that the nonlinear responseof such materials is mediated by the static structurefactor S(q) of the material, turning out to be stronglynonlocal. While the strength of the nonlinearity ispredominantly affected by the materialcompressibility, S(q) is strongly affected by thewhole structure of the soft-material phase, e.g. bythe presence of fractal aggregates which has impacton the nonlinear susceptibilities. [1]Thus, we have shown that specific nonlinear opticalprocesses, and in particular we have predicted theexistence of self-trapped optical beams, or “spatialsolutions” (SS). [1] These are light filaments whichcan propagate without diffraction, due to nonlinearresponse of the material. We have found a strictFig. 2: Numerical simulations of laser beampropagation in a soft material in the presence ofaggregates with fractal dimensions D=1.3 (a) andD=2.3 (b). The laser intensity distribution at theoutput plane of a soft-matter sample with lengthcomparable to the Rayleigh length of a beam withwaist w 0 profile is shown in a pseudo-color plot. Thenumber and the distribution of the laser filamentsgenerated from a Gaussian beam is strongly affectedby the fractal dimension.relation between the SS features, like the existencecurve relating the beam waist and power, withspecific structural quantities, like the cluster spatialextension, or their fractal dimensions. We have alsopredicted the existence of sub-wavelength ultra-thinSS than can propagate without diffraction, and thatcan have relevant applications for opticalcommunication devices or laser surgery (figure 1).We have also considered the role of disorder, e.g.due to density material fluctuactions, in thepropagation of a laser beam in a soft-material,including nonlinear effects. Specifically, we haveinvestigated the condition for the beam breakup intoa multitude of filaments, which propagate andinteract in due to the non local nonlinear response ofthe materials. A strong link with the materialstructure factor and these laser filamentation processcan be estabilished. (figure 2).[2]For what concern the experimental activity, weimplemented the z-scan techniques to measure thestatic and dynamic properties of the nonlinear opticalsusceptibility. We have reported specific evidences ofthe aging of the nonlinear susceptibility in Laponite,whose nonlinear optical response was augmented byadding a dye to the solution. [3]References[1] C. Conti, G. Ruocco, S. Trillo, Phys. Rev. Lett.96, 065702 (2006);[2] C. Conti, N. Ghofraniha, G. Ruocco, S. Trillo,submitted;[3] N. Ghofraniha, C. Conti, G. Ruocco, submitted.See the related chapter in this book.Fig. 1: Numerical simulation of the propagation of aself-trapped Gaussian beam in a soft-material withfractal dimension D=2.5, for two different inputpowers in the paraxial regime (a and b) and beyond(c and d), z 0 and w 0 are the diffraction length and thebeam waist respectively; z is the propagationdistance and r the transverse coordinate. [1].AuthorsC. Conti (a,b), N. Ghofraniha (c), G. Ruocco (b,d), S.Trillo (b,e).(a) Research Center “Enrico Fermi”, Rome, Italy.(b) CRS SOFT-INFM-CNR, Rome, Italy.(c) CRS SMC-INFM-CNR, Rome, Italy.(d) Universita’ di Roma, Rome, Italy.(e) Universita’ di Ferrara, Ferrara, Italy.67SOFT Scientific Report 2004-06

Scientific Report – Non Equilibrium Dynamics and ComplexityColloidal Suspensions Under ShearResearch activities in the field of colloidalsuspensions have recently exhibited rapid growth,for their relevance in both technical applications andfundamental science. On one hand, they areessential in many industrial application ranging frompaints to lubrificants, or in pharmaceuticalapplications such as drug delivery. On the otherhand, they play a preminent role as model systemsfor the principles of phase transitions in condensedmatter. One of the most peculiar behavoir of softcolloidal matter is the strong sensitivity of its flowproperties to external deformation. A systematicscientific comprehension about this topic is stillimmature.In the last few years we investigated the physicalmechanism governing the interaction between agingdynamics and shear flow in a Laponite suspension,which represents a prototype of a soft glassymeterial [2]. Dynamic light scattering has been usedto probe the relaxation of the intermediate scatteringfunction of the aging sample and the effect of shearon the non-equilibrium structural dynamics has beeninvestigated during various protocols of appliedshear. The shear flow influences significantly theaging dynamics as soon as structural relaxationenters the timescale set by the inverse shear rate(Fig. 1). Aging is strongly reduced in this sheardominated region, while for a fixed waiting time theaverage structural relaxation scales as the inverseshear rate.Fig. 2: Velocity profile of the Laponite sample putunder shear in a cone-plate cell, as a function ofthe distance along the gap of width H. Shearlocalization shows up next to the rotating cone wall.Shear rejuvenation of gelled samples has also beeninvestigated and we observed a substantiallydifferent aging regime characterized by a fasterrelaxation dynamics. In particular, the slowrelaxation time shows a power law dependence onthe waiting time after shear cessation.Another aspect of the soft glassy sample weinvestigated is the shear banding phenomena,characterizing yield stress fluids at low applied shearrates. Shear localization [4] has been observed inthe Laponite sample through heterodyne dynamiclight scattering technique (Fig. 2). The velocityprofile has been studied as a function of both thewaiting time and the applied shear rate. Theevolution of both the flow curve and the yield stressvalue is reflected locally in the evolution of the shearbanding velocity profile as the system ages. Finally,a periodic oscillation between two different velocityprofiles has also been observed, showing a stick-slipbehavior in the flow.Fig. 1 Slow relaxation time as a function of waitingtime during aging under different shear rates. Frombottom to top the shear rate value is: 446, 223, 67,22 s -1 . Solid symbols refer to aging without shear.Arrows in top frame indicate the inverse shear ratevalue corresponding to each curve. Deviation fromthe aging evolution is evident as soon as the slowrelaxation time reaches the timescale of the inverseshear rate.References[1] D. Bonn, S. Tanase, B. Abou, H. Tanaka, J.Meunier, Phys. Rev. Lett., 89, 015701 (2002).[2] P. Sollich, F. Lequeux, P. Hèbraud, M.E. Cates,Phys. Rev. Lett., 78, 2020 (1997).[3] R. Di Leonardo, F. Ianni, G. Ruocco, Phys. Rev.E, 71, 011505 (2005)[4] F. Varnik, L. Bocquet, J.-L. Barrat, L. Berthier,Phys. Rev. Lett. 90, 095702 (2003).AuthorsR. Di Leonardo, S. Gentilini, F. Ianni and G. Ruocco.SOFT CNR-INFM – Dipartimento di Fisica Universita’Roma ‘‘La Sapienza’’ – 00185 Roma – ItalySOFT Scientific Report 2004-0668

Multi-point Holographic Optical micro-VelocimetryMicron-sized particles can be hold stuck by light in a fluidflow. If the lights are turned off for a short time, particleswill be set free to flow for a short distance with the localfluid velocity. This is the core idea of Holographic Opticalmicro-Velocimetry [1], a newly developed technique whichis able to probe flow fields at those micro-scales which areso relevant for biology and micro-fluidics. The idea ofprobing fluid flows following freely flowing tracers has beenlargely applied by Particle Image Velocimetry, formacroscopic flows, and by its more recent miniaturizedversion for micro-fluidics. The main drawback of thisapproach consists in the need of continuously injecting ahigh concentration of tracers in the flowing fluid. This isrequired in order to cover all the interesting points inspace and to be able to average over the thermal noisealways affecting the trajectories of micron sized probes.This condition can be very restrictive in densely packedgeometries and heavily alter the function of theinvestigated micro-device. Holographic Optical micro-Velocimetry offers the possibility of choosing an arbitraryset of interesting points in the flow geometry and only usea small number of tracers, one for each measuring point.The tracers are held in place by the forces exerted by lighttraps. Light traps are submicron regions of high lightintensity whose distribution in space is dynamicallygenerated by a computer controlled hologram [2]. Micronsized dielectric particles are alternatively trapped andreleased from the trapping sites by chopping the trapbeam. Using digital video microscopy we can detect theprobe particles' displacements after a fixed delay timefrom release instant. The velocity field is thus mappeddirectly and simultaneously on the trap sites allowing toreconstruct the two dimensional projection of flow field onthe imaging plane in a three dimensional domain. Mostimportantly, the technique is independent of the trapcharacteristics, viscosity or temperature of the fluid.The validity of the technique has been demonstrated byFig. 2:. Azimuthal components of measured flowvelocities versus the corresponding radial distancefrom the centre of a spinning sphere. Solid linesrepresent the range of the expected velocityvalues for a sphere of radius R=3.7 µm spinning at5.2 Hz.Fig. 3: Measured flow field (arrows) at the outlet ofa 15 µm wide PDMS micro-channel.mapping out the fluid flow around a five microns spinningsphere (Fig.1,2) and at the outlet of a micro-channel(Fig.3). In the future tracers could be permanentlyembedded inside micro-fluidics devices or biologicalsystems and used to probe micro-flows during normaldevice operation.Fig. 1: Measured flow field (arrows) around a 4 µmradius vaterite particle spinning at 5.2 Hz(a) CRS SOFT-INFM-CNR, Roma, Italy.(b) Dipartimento di Fisica, Universita’ di Roma, Italy.References[1] R. Di Leonardo, J. Leach, H. Mushfique, J. Cooper, G.Ruocco, M. Padgett, Phys. Rev. Lett., 96, 134502,(2006).[2]D.G. Grier, Nature, 424, 810, (2003).AuthorsR. Di Leonardo (a), G. Ruocco (b,a)69SOFT Scientific Report 2004-06

Scientific Report – Non Equilibrium Dynamics and ComplexityPolymeric Elements For Adaptive NetworksWe consider an adaptive network to be a system ofinput and output electrodes, connected through acomplex net of nonlinear elements and “intelligent”wires, providing numerous possible pathways forsignal propagation from each input to each output.Characteristic feature of the network is the possibilityof the establishing preferential pathways accordingto the previous experience of the system (“learning”)and to the training procedure performed by externalaction. Thus, a specific output signal will appear incorrespondence with a given input signal or asequence of input signals. However, to be reallyadaptive, the network must have temporal evolutionof these connections, and must allow the variation ofthe input-output relationships according to the“learning” or if the new information from the externaltraining appears (“teaching”). A final feature of thenetwork is its topological complexity: such parametershould influence strongly the efficiency of theaforementioned processes.The only known perfectly working adaptive system,namely, the neuron network of biological cognitivesystems, is constructed from organic molecules anduses electrochemical principles for most of itsfunctioning. Furthermore, the adaptive mechanismswe wish to consider are conceptually similar to theso-called Hebbian rule [1] which is at the basis ofmodern neuroscience. Thus it is of interest to searchfor an organic complex adaptive network inspired byneurosystems.Within this general research program, we haveobtained the following results:1. We have fabricated and characterized anelectrochemically controlled non linear polymericheterostructure [2] Such structure should mimic inCurrent (A)7.0E-086.0E-085.0E-080.0E+00 2.0E+03 4.0E+03 6.0E+03 8.0E+03Time (s)Fig. 2: Temporal behaviour of the current of thepolymeric analog of generating neuron.our network the functional behavior of synapses inbiological cognitive systems. In particular, we havefound an asymmetric behavior in the time relaxationof the electrochemically controlled current, which isessential for the adaptive behavior we seek.2. We have shown that our device, with some smallbut essential modifications, can have self-sustainingcurrent oscillations for constant applied bias. Thismakes our device analogous to the so-calledgenerating neurons. In the case of the pond snail,Lymnaea stagnalis, which we chose as our biologicalbenchmark, this corresponds to the N1M neuron [3].Furthermore, we have some preliminary evidencethat such oscillations may be similar to the wellknown Bielousov-Zhavatinski reaction [4].3. We have also verified the possibility of usingstatistical assembly to create mixed networks of ourbasic polymeric components, namely doped PEO anddoped PANI fibers, in which due to sufficiently highcomplexity the probability of the occurrence ofjunctions with the same characteristics of ourfabricated PEO-PANI heterojunction is high [5].bReferences[1] D.O. Hebb, The organization of behavior: Aneuropsychological Theory, Wiley Sons, NY (1961).[2] V. Erokhin, Y. Berzina, and M.P. Fontana, J. Appl.Phys., 97, 064501 (2005).[3] V.A. Straub, K. Staras, G. Kemenes and P.R.Benjamin, J. Neurophysiol., 88, 1569 (2002).[4] V. Erokhin, T. Berzina, M.P. Fontana, Crystallogr.Rep., in press (2006).[5] V. Erokhin, T. Berzina, P. Camorani, M.P.Fontana, manuscript submittedAuthorsV. Erokhin, T. Berzina, and M.P. FontanaUniversity of ParmaCRS SOFT CNR-INFMFig. 1: Temporal behaviour of the current of thepolymeric synapses analog for positive (a) andnegative (b) bias.SOFT Scientific Report 2004-0670

Aging of the Nonlinear Optical SusceptibilityNonlinear optics susceptibility of liquids e. g. organicdye solutions have been widely studied by examiningnonlinear refraction of thermal origin and nonlinearabsorption of electronic origin. However in ourknowledge optical nonlinear response variations inpresence of structural dynamics slowing down(aging) in soft materials such as colloidalsuspensions have not been considered. With thisaim, we investigated on a system of Laponite claypowder dispersed in dye Rhodamine-B aqueoussolution, displaying high thermal nonlinear opticalresponse and the gelation process characteristic ofthe clay suspension [1].We performed Z-scan [2] and dynamic lightscattering (DLS) measurements to show that opticalnonlinearities exhibit the same aging behaviour ofstructural dynamics of a system.We present, as an example, in Fig. 1 Z-scan curves(A) of 0.6mM RhB aqueous solution at 2.2 wt % claydispersion at increasing waiting time t wcorrespondingly to the correlation functions (B),from which is evident the dynamics slowing down ofthe system for increasing aging time. In Fig. 1A isalso reported the 0.6 mM RhB solution transmittancecurve (open circles) and it is worth noticing thatoptical nonlinearities are influenced by Laponitepresence and more interestingly dye nonlinearsusceptibility does vary in the clay matrix undergoingaging. The transmittance curves in Fig. 1A are typicalof beam defocusing nonlinear systems in this casewith thermal lens-like behaviour, in fact, as it is wellknown, dye molecules are characterized by stronglight absorption giving rise to refractive indexgradient due to the thermal effect. MoreoverRhodamines are characterized by nonlinear saturableabsorption as a result of excited-state or two photonabsorption well described in [3]. We used theanalytical description of Z-scan method reported in[4] to estimate both nonlinear refractive index andabsorption coefficient of the 0.6 mM RhB- Laponitedispersions at different clay concentrations. In Fig 2Aand Fig 3A mean relaxation times τ m given by fittingDLS data and nonlinear absorption coefficients fromZ-scan measurements are reported vs. tw. Thespecific t w dependence of τ m(t w) and α 2(t w) leads toconsider a scaling law, that makes all data collapseFig. 1: Z-scan spectra (A) and DLS correlationfunctions (B) of Laponite 2.2 wt % dispersion inRhB 0.6 mM water solution for different waitingtimes t w and corresponding fits (full lines). In A isalso reported RhB 0.6 mM scan (open circles).Fig. 2: Mean relaxation time τ m vs. waiting time t w(A) and vs. the scaled variable µ τ t w (B) in loglinearscale at various clay concentrations; full linesin (A) are the fitted curves.on a single master curve. This curves are reportedrespectively in Fig. 2B and Fig. 3B as functions ofµ τ t w and µ α t w, being µ τ and µ α fitting parameters [5].From our analysis it emerges that the two timescales µ τ -1 and µ α -1 are comparable showing that thenonlinear optical susceptibility does age andmoreover it exhibits the same aging behaviour ofstructural dynamics.Fig. 3: Nonlinear absorption coefficient α 2 vs. waitingtime t w (A) and vs. the scaled variable µ α t w (B) atvarious clay concentrations; full lines in (A) are thefitted curves.References[1] B. Ruzicka, L. Zulian and G. Ruocco, Phys. Rev.Lett. 93, 258301 (2004);[2] M. Sheik-Bahae, A. A. Said, Tai-Huei Wei, D. J.Hagan and E. W. Van Stryland, IEEE J. Quant. El. 26(4), 760 (1990);[3] N. K. M. Naga Scrivinas, S. Venugopal Rao andD. Narayana Rao, J. Opt. Soc. Am. B 20 (12), 2470(2003);[4] R. E. Samad and N. D. Vieira, J. Opt. Soc. Am. B15(11) (1998);[5] N. Ghofraniha, C. Conti, G. Ruocco, preprint.AuthorsN. Ghofraniha (a), C. Conti (b,c), G. Ruocco (d,c).(a) SMC-INFM-CNR, Università di Roma, Italy.(b) Research Center “Enrico Fermi”.(c) SOFT INFM-CNR, Università di Roma, Italy(d) Dipartimento di Fisica, Università di Roma, Italy.71SOFT Scientific Report 2004-06

Scientific Report – Non Equilibrium Dynamics and ComplexityRubberlike Dynamics in Sulphur Above the λ-TransitionTemperatureAt 432 K (Tλ) and ambient pressure, liquid sulphurundergoes a rather peculiar reversible transitionbetween a yellow low viscosity fluid to a reddish highviscosity one. This phenomenon, known as λtransition, is marked by anomalous behaviour inmany physical properties. In particular, the shearviscosity increases by at least 4 orders of magnitude[1] and a λ-like singularity is found in thetemperature dependence of the heat capacity [2].The transition is generally attributed to a reversiblepolymerization process: the S8 units of the lowtemperaturemolecular liquid tend to open above Tλand to polymerize, thus giving rise to a solution ofpolymers in monomeric S8 molecules.An inelastic x-ray scattering (IXS) study of the highfrequency acoustic dynamics of sulphur across Tλhas been performed [3], measuring the wavenumber (q) and energy (E) dependence of thedynamic structure factor S(q,E) at five temperaturesacross Tλ. At each temperature, spectra werecollected at values of q between 1 and 15 nm -1 andin the ±20 meV energy range. The resulting spectraare characterized by a quasielastic contribution andan inelastic Brillouin doublet. The data have beenfitted to a DHO model function and thus described interms of three relevant quantities: the energyposition Ω of the Brillouin peak, its FWHM, 2Γ, andthe ratio of the elastic to the total spectral intensityfq.At all the investigated temperatures, a linear qdependence of Ω and a quadratic dependence of 2Γhas been identified up to q ~4 nm -1 . These resultsindicate that liquid sulphur behaves as a viscoelasticliquid, and that, at the high frequencies probed byIXS, its unrelaxed elastic properties are beingmeasured.The sound velocity v∞ has been derived from theslope of Ω(q) and the longitudinal kinematic viscosityν l, as well, from 2Γ(q). The velocity (fig. 1, top) is40% higher than that measured with ultrasonictechniques; the low-q limit of the experimental fqvalues is in agreement with the hydrodynamicprediction, obtained assuming v∞ to be the limitinghigh frequency sound speed.The corresponding viscoelastic transition, whichtakes place between the MHz and the THz frequencyrange probed by IXS, is most likely the structuralrelaxation, that characterizes the dynamics of allliquids. The data show that the structural relaxationexperiences fundamentally no change at Tλ (fig. 1,top): the structural relaxation is thus, surprisingly,not responsible for the increase of the shear viscosityacross the λ transition.By supposing that structural relaxation is the onlyone active in liquid sulphur and using a constantratio between ν l and ν t (the kinematic shearviscosity), a strong increase of the ultrasonicacoustic attenuation should be expected. Theabsence of this feature in the data (fig. 1, bottom)clearly indicates the existence of an additional lowfrequency relaxation.This low frequency relaxation can be attributed toentanglement coupling among polymeric chains,typical of concentrated solutions of linear uncrosslinkedpolymers. Results available in the literaturecan be used to guess a characteristic time in the msrange and a strength in the order of 10 5 Pa for theshear modulus.References[1] R.F. Bacon and R. Fanelli , J. Am. Chem. Soc.65, 639 (1943).[2] F. Feher and E. Hellwig, Z. Anorg. Allg. Chem.294, 63 (1958)[3] G. Monaco, L. Crapanzano, R. Bellissent, W.Crichton, D. Fioretto, M.Mezouar, F. Scarponi And R.Verbeni, Phys. Rev. Lett. 95, 255502 (2005)• Fig. 1: Temperature dependance of a) soundvelocity and b) line-width divided by q 2 . TheIXS results (■) are reported together withultrasound data. In a) the dotted line puts inevidence the change in the temperaturecoefficient of v ∞ at T λ. In (b) the dashed curveis the zero-frequency, symple hdrodynamicsprediction.AuthorsG. Monaco (a), L. Crapanzano (a), R. Bellissent (b),W. Crichton (a), D. Fioretto (c,d), M. Mezouar (a), F.Scarponi (c,d) and R. Verbeni (a)(a) ESRF, Grenoble, (FR) (b) Centre d’EtudiesNucleaires, Grenoble, (FR) (c) Dipartimento di Fisica,Università di Perugia, (IT) (d) INFM CRS-SOFT c/oUniversità di Roma ″La Sapienza″ , Roma, (IT).SOFT Scientific Report 2004-0672

Tackling the λ-transition in liquid Sulphur by InfraRed PhotonCorrelation SpectroscopyDeveloping a novel experimental technique, we appliedInfrared Radiation Photon Correlation Spectroscopy(IRPCS) to liquid sulphur in the λ transition region, i.e.where an abrupt increase in viscosity by four orders ofmagnitude has been observed upon heating within fewdegrees [1]. According to basic paradigms, thisincrease in viscosity around T λ=159 °C should inprinciple trigger an equivalent increase of thestructural relaxation time τ α from the ps to the nsrange, according to the Maxwell equation η=G ∞·τ α, G ∞being the limiting short wavelength shear modulus.This should imply, in turn, the detection of a relaxationeffect crossing the GHz frequency domain by means oftechniques, like Brillouin light scattering (BLS), thatmeasure the longitudinal elastic modulus, and a largeincrease in attenuation at ultrasonic frequencies. BLShas shown [2], on the contrary, a continuous smoothdecrease in the real and imaginary part of themodulus, testifying a decrease of τ α. Ultrasonicexperiments performed in the 1-10 MHz frequencywindow [3] did non evidence, as well, any criticalvariation of the acoustic attenuation around T λ;sulphur thus escaped the established viscoelasticframework for over a century, warranting the title of “viscous but not viscoelastic liquid” [3]. IRPCS wasperformed using a diode pumped solid state lasersource operating at λ = 1064 nm. The detector was aPerkin Elmer avalanche photodiode retaining a 2%quantum efficiency at the probe wavelength, with a 50counts/s dark count and an after pulse probabilitylower than 3%. The 90° scattered radiation wascollected by a lens and collimated by means of an IRoptimized collimator from OZ-optics. The sample waskept in a home-made furnace whose temperature wasmeasured by a RTD and stabilized by a software PIDfeedback. The digital signal coming out from the• Fig. 1: Reduced homodyne IR correlationfunctions at selected temperatures. Opensymbols are for TT λ. The temperature behaviour of thedetector was acquired by a PC and used to performreal time autocorrelation. Correlation functions werecollected at constant temperatures during an upscan inthe range 145

Scientific Report – Non Equilibrium Dynamics and ComplexityVibrational Dynamics and Viscous Flowin Glass Forming LiquidsThe connection between slow and fast degrees offreedom in glass forming materials has been in focusof several investigations for long times. On thetheoretical side, landscape based approachessuggest a correlation between the curvature of thepotential energy minima and the barrier heights. Onthe experimental side, a number of correlationsbetween the temperature dependence of theviscosity (fragility) and other quantities related tofast degrees of freedom gradually emerged. A newimpulse in this context has been stimulated by arecently reported result connecting fragility with thelow temperature behaviour of the non ergodicityfactor.When reported on an Arrhenius plot, i.e. logarithm ofviscosity versus inverse temperature, practically allglass forming liquids stand in such a way that theycan be ordered according to their steepness at theglass transition temperature, T g. On a morequantitative groung, one defines the kinetic fragilitym as:m =limT →Tgd logηd(T T )Recent extensive inelastic x-ray scattering (IXS)measurements of the dynamic structure factor haveallowed to constitute a sizeable library of highfrequency (THz) dynamical properties of glasses. Inparticular, the IXS measurements allow for thedetermination of the non-ergodicity factor, f(Q,T),i.e. the long time limit of the normalized densitydensitycorrelation function. This quantity representsthe amount of decorrelation introduced by thevibrational dynamics, and it depends on both the (Tdependent)amplitude of the vibrations and thedegree of disorder of the glassy structure.We show that the low temperature dependence ofthe non ergodicity factor for several glasses stands ina fashion similar to the one exhibited by a T g scaledArrhenius plot (best known as Angell plot). It isindeed possible to define a glass fragility as thederivative of f(Q,T) in the T=0 limit (there is almostno Q dependence in the small Q region of interesthere) .mαdf ( Q,T )= limT → 0 d(T T )This conceptually suprising link between vibrationalmotion in glasses and diffusive processes insupercooled liquids represents a further aspect thatrequires to be clarified and, at the same time,suggests a new direction of investigation for the theultimate understanding of the glass transitionphenomenology.ggfragility m12010080604020BeF 2silicaglycerolPB 1.4mTCP00.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8SeoTPmtolsalolnBBFig. 1. Upper panel: Angell plot for a strong,intermediate and fragile system. Middle panel: Glassfragility for the same three system. Lower panel:Correlation between liquid and glass fragilityReferences[1] C.A. Angell, Science, 267, 1924 (1995)[2] T. Scopigno, G. Ruocco, F. Sette and G. Monaco,Science 302, 850 (2003).[3] V.N. Novikov. A.P. Sokolov, Nature 431, 961 (2004)[4] J. Dyre, Nature Materials 3, 749, (2004)AuthorsG. Monaco (a), G. Ruocco (b,c), T. Scopigno (c), F.Sette (a).(a) ESRF, Grenoble, France.(b) Dip. Di Fisica, Univ. Di Roma, Roma, Italy.(c) CRS SOFT-INFM-CNR, Roma, Italy.αSOFT Scientific Report 2004-0674

The low-energy excess of vibrational states inv-SiO2: the role of transverse dynamicsInsulating disordered solids exhibit some commonpeculiarities in their low-temperature and low-energydynamics, including an excess of modes in thevibrational density of states, known as the bosonpeak (BP). An unambiguous understanding of theseextra modes, and of their possible relation with otheranomalies, is still lacking, In the case of v-SiO2, themost widely accepted explanation is that the BPoriginates from the piling up of modes near the firstvan Hove singularity of the transverse acousticvibrational branch. In addition to the ambientpressure data, useful information is available for v-SiO2 at higher densities: densification results in ashift of the BP towards higher energies and in asimultaneous decrease of its intensity.a weak shoulder in the transverse spectra only at Q> 10 nm −1 . We assign this feature to the longitudinalsound-like branch. The behaviour of the low energyexcitation is complementary: it is always present inthe transverse spectra, while it appears in thelongitudinal currents only at Q > 8 nm−1. At smallQ, the low energy peak disperses linearly with asound velocity of ≈3800 ms −1 (appropriate for thetransverse sound modes), and becomes almost nondispersingat Q > 8 nm−1. This feature —which isthe main one in the transverse spectra— is thetransverse acoustic mode. The presence of thesignature of transverse dynamics in the longitudinalcurrent spectra, and vice versa, is due to the factthat the polarization character of the modes becomesill defined at short wavelengths. Spectra for thesample at the highest density studied (ρ=4.0 gcm −3 ), are reported in the right panels of the figure.One can observe that no evidence of wronglypolarized modes is present; moreover, the T branchno longer shows a flattening.The conclusion that can be drawn is that the excessof states in the normal sample accumulates in aregion, which is almost coincident with the energyrange where the transverse branch flattens,indicating that the BP arises from the high Q portionof the transverse branch. This assignment isconfirmed by the behaviour of the high-energytransverse dynamics upon densification.Fig. 1 - Longitudinal (full) and transverse (dashed)current spectra at selected Q values (nm −1 ) for ρ =2.2 (left) and 4.0 rigt) g cm −3 .We present here simulation results on v- SiO 2 atdifferent densities which help in clarifying the originand the nature of the excess modes, as well as theintensity and shift effects on the BP as a function ofdensity.The systems investigated consist of 680 SiO 2 units(N=2040 ions), enclosed in cubic boxes of differentlengths (from L=3.1359 nm, ρ=2.2 g*cm −3 for theglass at room pressure, down to L=2.5693 nm,density ρ=4.0 g*cm −3 ), with periodic boundaryconditions. The ions interact through the BKS [31]two-body potential.We have computed the dynamic structure factorS(Q,ω) and the longitudinal (L) and transverse (T)current spectra C L,T(Q,ω). In figure 1, left panel, wereport longitudinal and transverse current spectra atselected Q values for the uncompressed sample (ρ =2.2 g cm−3). For Q larger than about 8 nm −1 , bothCL(Q,ω) and CT(Q,ω) show two distinct maxima, andthis structure becomes more and more evident withincreasing Q. The excitation at higher energydisperses with Q and is observed at all Q values inthe longitudinal current spectra, while it shows up asExperimentally, it is observed that upon densification(i) the BP shifts to higher energy and (ii) its intensitystrongly decreases. From our simulations we observethat, by increasing the density, the T branch flattensat a higher energy and, upon further densification,no flattening is observed at all. A similar behaviour isobserved for the calculated density of states as afunction of density [1]: the low-energy part of theDOS shifts to higher energies and decreases inintensity. As a consequence, the BP stronglydecreases in intensity and shifts to high energies [1].References[1] O. Pilla et al., J. Phys. Cond. Mat. 16, 8519(2004).Authors:O. Pilla (1), S. Caponi (1,2), A. Fontana (1,2), J.R.Goncalves (1,3), M. Montagna (1), F. Rossi (1), G.Viliani (1,2), L. Angelani (4,5), G. Ruocco (2,4), G.Monaco (6), F. Sette (6) - (1) Dipartimento di Fisica,Università di Trento, Italy; (2) INFM-CRS SOFT,Università di Roma La Sapienza, Italy; (3)Departamento de Fısica, Universidade do Cearà,Brazil; (4) Dipartimento di Fisica, Universit`a diRoma La Sapienza, Italy(5) INFM-CRS SMC,Universit`a di Roma La Sapienza, Italy; (6) EuropeanSynchrotron Radiation Facility, Grenoble, France75SOFT Scientific Report 2004-06

Scientific Report – Non Equilibrium Dynamics and ComplexityDroplets of Liquid Gallium Under High Temperature and HighPressure ConditionsIn the last few years the study of liquidpolymorphism has received a great attention. Theexistence of two possible distinct liquids, with thesame chemical composition but with differentphysical properties is quite consistent withexperimental data and theoretical predictions.Liquid-liquid phase transition has been related to thesoft-core interaction potential characterized by thecoexistence of metallic and covalent behaviour in thebonding (for example as liquid Sn, Bi, Ga or Ge). Inprinciple Gallium is one of the best candidate forshowing liquid polymorphism. This is due to twoprincipal reason: one its ice-type phase diagram witha negative temperature dependence and the secondone because its display extended polymorphism inthe solid phase. The samples we investigatedconsist of gallium droplets (~ 4% weight) inserted inan inert matrix of mixed epoxy resin and LiF. Weperform on our sample different spectroscopictechniques: X-ray absorption on Ga K-edge level(XAS) , single x-ray absorption detection (SEXAD)and energy x-ray diffraction (ESXD). Ourmeasurements were performed at the BM29 of theESRF facility using a Paris-Edimburgh large volumecell in a range of pressure up to 6.7 Gpa and atemperature range of 298-440 K. In the next figurewe show the behaviour of the x-ray diffractionspectra as function of the pressure where it ispossible to observe clearly the appearance of Ga(III)crystalline phase Bragg peaks above 4.2 GPa(channel 2) whereas no Ga(III) (013) peak isdetected at 2.3 GPa (channel 3). It is important tonote the appearance of Ga(III) in a region wherethat Ga(II) has a stable crystalline phase. In thesame figure on the right side temperature scans(SEXAD) recorded at different pressure are reported,and it is possible to see the discontinuities relatedwith the solid-liquid phase transition. The increasingdiscontinuities observed as function of pressureFig. 2.confirms the occurrence of a partial crystallization ofthe gallium droplets.In the following picture the XAS measurements in anenergy interval close the Ga-edge for two differentthermal histories are reported. We can observe aobvious change in the absorption in the liquid phaseobtained between 1.6 GPa and 0 GPa and this mayindicate the occurrence of a possible transformationin the microscopic structure or/and in the electronicstate.Moreover the shape of the difference signal (blackcurve) it is quite different from the one obtainedbetween the 5.8 and 2.7 GPa spectra and alsodifferent from a typical Da(E) curve of twoequilibrium liquid Ga XAS spectra (right panel). Thisresult may infer the existence of a different liquidphase above 1.6 Gpa.So considering both ESXD and SEXAD spectra wecan observe that the quantity of crystallized galliumdroplets increases as function of pressure while noevidence of crystallization is observed up to 2.6 Gpa,well under the melting point line at roomtemperature.In conclusion the interesting hypothesis of a liquidliquidphase transition occurring between 0 and 1.6GPa is compatible with our results and it spursfurther investigation on this systems.References[1] R. Poloni, S. De Panfilis, A. Di Cicco, G. Pratesi,E. Principi, A. Trapananti, and A. Filipponi "Liquidgallium in confined droplets under high-temperatureand high-pressure conditions", Phys. Rev. B 71,184111 (2005).AuthorsR. Poloni, S. De Panfilis, A. Di Cicco, G. Pratesi, E.Principi, A. Trapananti, and A. FilipponiFig. 1.SOFT Scientific Report 2004-0676

Vibrational properties of inclusion complexes: the case ofindomethacin-cyclodextrinCyclodextrins (CD) are a family of cyclicmolecules, consisting of six (α-CD), seven (β-CD) oreight (γ-CD) glucopyranose units which, in water,take on the peculiar 3-dimensional structure of atruncated cone, with a slightly soluble outer surfaceand a hydrophobic central cavity. A remarkableproperty of CD in aqueous solution, is their ability toform host-guest inclusion complexes with a widevariety of organic and inorganic molecules, providedthat the guest molecule is less polar than water. Inparticular, inclusion complexes of CD with non-polardrugs are a topic of current interest, because thesenon-covalent complexes increase the aqueoussolubility of drugs and also their chemical stabilityand bioavailability.Among the non-steroidal anti-inflammatorydrugs, indomethacin (IMC) is widely used as ananalgesic drug in the treatment of rheumatoidarthritis, as well as in other degenerative jointdiseases, and recently it has also shown anti-tumouractivity. Nevertheless, due to its chemical structure,IMC is poorly soluble in water and this reduces itstherapeutic applications. A strategy to affect itssolubility and chemical stability in water, which isactually employed in commercial drugs, consists inthe preparation of inclusion complexes with CD.In a recent paper [1] we discuss the resultsof Raman scattering experiments and numericsimulations on the IMC-CD inclusion complexes insolid state, which provide new insight into thestructure of the complexes, and into the effect of theinclusion process on the guest. Inclusion complexesof IMC with hydroxypropylβCD (IMC-HPβCD) andCD (IMC-βCD) have been prepared and preliminaryexperiments have been performed on the sampleusing electrospray-ionization mass spectrometry andNMR, in order to verify the effective formation of thecomplexes and their stoichiometry.also confirmed by the vibrational analysis performedby ab initio quantum chemical computation. Bycomparing the spectrum of free IMC (Fig.1 (a)) tothose of its inclusion complexes IMC-HPβCD (Fig.1(b)) and IMC-βCD (Fig.1 (c)), we note a markedbroadening of the peak corresponding to the amideC=O stretch, as well as a shift from ≈ 1700 cm -1 to ≈1670 cm -1 .From the above results one might infer thatit is the amide C=O group of IMC (and theneighbouring atoms) to be most affected by theinclusion process; similar results have been obtainedalso on the inclusion complex formed by βCD withIMC sodium salt. Moreover, in order to understandthe precise way in which such atoms are influencedby complexation, other possible effects should bediscussed, such as the possibility that the changes ofvibrational frequencies be due to the presence of theuncomplexed guest in dimer form. However, all theexperimental results indicate that the observed shiftof the amide C=O stretch is actually related tocomplexation and not to the cleavage of hydrogenbonding patterns of IMC dimers.Experimental results are in qualitativeagreement with the conclusion of simulation, asshown in Figure 2., where the effect of thecomplexation on the computed g(ω) is reported. Wenote that here the shift to lower energy of theeigenvalue at 1628 cm -1 (corresponding in thesimulation to the amide C=O stretch of IMC) is wellreproduced.g(ω)1628 cm -1free IMCfree βCDIMC-βCD complex1614 cm -11620 1650 1680Energy (cm -1 )Fig. 2 Calculated g(ω) for free IMC (full line), freeβCD (empty circles) and for IMC-βCD inclusioncomplex (dotted line)Fig. 1 Raman spectra of free IMC (a), IMC-HPβCDcomplex (b) and IMC-βCD complex (c).By comparing the Raman spectrum of freeIMC with that of other molecules which havechemical structure very similar to subunits of IMC,we have assigned the peak of the guest at 1698 cm -1to the amide C=O stretch. This assignment has beenReferences[1] B. Rossi, P. Verrocchio, G. Viliani, G. Scarduelli,G. Guella, I. Mancini, J. Chem. Phys. 125 044511(2006).Authors: B. Rossi (a,b), P. Verrocchio (a,b), G.Viliani (a,b), G. Scarduelli (a), G. Guella (a), I.Mancini (a) - (a) Dipartimento di Fisica Università diTrento, Italy; (b) INFM CRS-SOFT, c/o Università diRoma "La Sapienza", Roma, Italy77SOFT Scientific Report 2004-06

Scientific Report – Non Equilibrium Dynamics and ComplexityTemperature-dependent vibrational heterogeneitiesin harmonic glassesThe question as to whether the structure of glassesat the scale of tens to hundreds of interatomicdistances is homogeneous or inhomogeneous, hasattracted recently much interest. Traditionally,following the continuous random network modelsuggested by Zachariasen, the homogeneoushypothesis has prevailed, also because noheterogeneity was clearly observed by small-angleneutron or X-ray scattering and electron microscopy.However, these techniques show only that there isno density heterogeneity, but tell nothing about thecohesion at the nano-metric scale, and cannot ruleout vibrational dynamical heterogeneities.Actually, recent molecular dynamics simulations onbinary Lennard-Jones (LJ) mixtures showed that inthe supercooled state highly mobile and immobileparticles exist, which are spatially correlated over arange that grows with temperature as the glasstransition is approached.the local force constants, motion in a given directionwill only occur if allowed by the excitable modes. Astemperature is increased and higher-energy modesbecome appreciably excited, the displacementpatterns will be changed, and the same is expectedto happen to the characteristics of theheterogeneities.Our mono-atomic samples consisted of N 0 = 6980,2048, 1500, 1000, and 500 atoms, interactingthrough the LJ pair potential with parameters, massand density suitable for Argon. The soft (hard) atomshave been identified as those with small (large)variation of potential energy under the displacementpattern produced by all (temperature-weighed)normal modes.The presence of vibrational heterogeneities isdetected by comparing the pair correlation functionof the whole system, g W(R), to that of the Nsoftest/hardest atoms, g N(R). An excess ofcorrelation in the peaks corresponding to nearestneighbours(nn) and next-nearest neighbours, i.e. g N> g W, indicates the existence of heterogeneity. InFig. 1 we report the pair correlation functions of the2048-atom LJ system for various numbers of soft (a)and hard (b) atoms, at T = 03 in units of themaximum frequency. Clear differences appear in thefirst peak for both classes.One important question is whether with the presentsystem size it is possible to estimate the dimensionthat the dynamical heterogeneities would have in an"infinite" sample. To evaluate the size of theheterogeneities, we evaluated the ratio g N/g W; thedistance R 0 at which it stabilizes around 1, can beconsidered as an indication of the "radius" of theheterogeneity. The estimated size of heterogeneitiesdoes not depend very much on the sample size, andresults to be of the order of 7.5 ºA.Fig. 1 Pair correlation functions for N 0 = 2048(averaged over 3 samples). Top panels: differentnumber of soft (a) and hard (b) atoms, at ¯fixed T =0.3. Bottom panels: different temperatures for the200 softest (c) and hardest (d) atoms.One important issue is whether or not suchheterogeneities are, in some sense, "frozen down"through the glass transition, so that even in the cold,harmonic glass, they leave a memory and, as aconsequence, softer and harder zones exist. In thepresent paper [1] we are concerned with two mainaspects of this problem: on the one hand we look forthe existence of dynamical heterogeneities in 3-dimensional harmonic LJ glasses, and investigatetheir size; on the other hand, we study the effect oftemperature. The latter is expected on the basis ofthe following argument. Consider a harmonic glass atlow temperature; in this case only the modes of lowfrequency will be excited and the atoms will onlyperform the cooperative motions corresponding tothese ; therefore, irrespective of the magnitude ofReferences[1] B. Rossi, G. Viliani, E. Duval, W. Garber,Europhysics Letters 71 256 (2005).Authors:B. Rossi (a,b), G. Viliani (a,b), E. Duval (c), W.Garber (d) - (a) Dipartimento di Fisica Università diTrento, Italy; (b) INFM CRS-SOFT, c/o Università diRoma "La Sapienza", Roma, Italy ; (c) LPCML, UMR-CNRS 5620, Université Lyon I, 69622 VilleurbanneCedex, France; (d) Department of AppliedMathematics and Statistics, Stony Brook University,Stony Brook, New York 11794-3600, USASOFT Scientific Report 2004-0678

Aging in Charged Colloidal SystemsColloidal dispersions are a very interesting class ofmatter. Due to their rich phenomenology andproperties they can be used to test a large variety oftheoretical models, or vice versa theories can besubjected to stringent experimental tests. In somecases in fact the inter-particle interactions can betuned almost ad-hoc, e. g. by changing the ionicstrength in the system. In this context the study ofLaponite system is particularly intriguing. LaponiteRD is a disk like clay particle with a well definedthickness of 2H=1 nm and a diameter of about2R=30 nm (fig. 1A). When laponite is dispersed inwater a strong negative charge appears on faceswhile, depending on the pH of the solution, a weakpositive or negative charge appears on the rim.Therefore in this colloidal system long rangeelectrostatic repulsion and short range attractiveinteractions are both present and the competitionbetween the two interactions makes Laponitesuspensions even more interesting.In particular a new phase diagram has shown as wecan be in presence of phase separation, liquid,attractive gel, attractive or repulsive glass, justchanging the clay amount and/or the presence ofsalt in the solutions [2]. For this reasons we canconsider Laponite suspensions as a model system todescribe disk like charged particles in presence ofboth short range attraction and long range repulsion.We performed a dynamic light scattering study of theaging phenomenology in laponite dispersions inwater, varying clay and salt concentrations. Allsamples studied, surprisingly also those predicted tobe in a liquid stable phase, experience aging (fig.1B).After a certain waiting time, starting when thesample is filtered, a non ergodic state is reached asshown from an incomplete decay of theautocorrelation function (fig.1B). More the sample isconcentrated less is the waiting time necessary toobtain an arrested phase. Moreover, at a fixedlaponite concentration, this time decreases withadding salt, reflecting the screening of the repulsivepart of the interaction between particles. All theautocorrelation data show two dynamical regimes.The fast “diffusive” behavior is described by a singleexponential decay with a fast relaxation time τ 1. Theslow one is well described by a stretched exponentialdecay defined by the relaxation time τ 2 and thestretching exponent β. From the analysis of thewaiting time behavior of the slow dynamics it ispossible to identify two dynamical routes to reach afinal arrested state, one at "low" (open circles in fig.1C) and one at "high" (full circles in fig. 1C) clayconcentrations. This dynamical difference should bea signature of two different structuralrearrangements of the system realized because ofthe competition between the repulsive and theattractive parts of the potential. These new resultsdetermines a redrawn of a part of the phase diagram(fig. 1C). In particular the predicted liquid region (ILin fig. 1C) is found not to be a stable phase, aspreviously determined, but an arrested phase.Moreover the presence of two different arrestedstates, one at "low" and one at "high" clayconcentrations, and a transition line between themare identified [3],[4] .References[1] A. Mourchid, A. Delville, J. Lambard, E. Lecolier,and P. Levitz, Langmuir 11, 1942 (1995).[2] H. Tanaka, J. Meunier, and D. Bonn, Phys. Rev. E69, 031404 (2004).[3] B. Ruzicka, L.Zulian and G. Ruocco, Phys. Rev.Lett. 93, 258301 (2004).[4] B. Ruzicka, L.Zulian and G. Ruocco, Langmuir,22, 1106 (2006).Fig.1: (A) Laponite crystal. (B) Agingphenomenon in sample with C w=1.0%, C s=2x10 -3 M. (C) Phase diagram of Laponite dispersion, thered line indicates the hypothesized new transitionline between two different arrested states.AuthorsB. Ruzicka (a), L. Zulian (b,a), G. Ruocco (c,a)(a) CRS SOFT-CNR-INFM, c/o Universita’ di Roma« La Sapienza » P.le A. Moro 2, 00185 Roma.(b) Dipartimento di Fisica Universita’ degli studi diPerugia, via A. Pascoli 06123, Perugia, Italy.(c) Dipartimento di Fisica, Universita’ Roma « LaSapienza », P.le A. Moro 2, 00185, Roma, Italy.79SOFT Scientific Report 2004-06

Scientific Report – Non Equilibrium Dynamics and ComplexityMatter Under High PressureHigh pressure amorphyzation of carbon dioxideAmong the group IV elements, carbon is the uniquethat at ambient condition forms stable double bondswith oxygen. In contrast to the cases of SiO2 andGeO2 the nonmolecular tetrahedral crystalline formof CO2, phase V, only exists at high pressure.Similarly, while the amorphous phases of SiO2 (asilica)and GeO2 (a-germania) are well known andstable at room condition, the amorphous,nonmolecular, phase of CO2, although predicted byab-initio simulations, had not yet been discovered.Byusing a resistive heated Diamond Anvil Cell we couldsynthesize amorphous, silica-like, carbon dioxide.The non molecular amorphous phase of carbondioxide, a-CO2, that for similarity with othera-CO 2100 µmFig. 1. Photograph of Carbonia at 61 GPa. androom temperature. The sample is transparent andspatially homogeneous.amorphous oxide of the group IV we have called a-carbonia, was attained by compressing molecularphase III above 47 GPa at room temperature.In situ infrared spectra, measured with raisingtemperature up to 680 K, probe the progressiveformation of C-O single bonds and the simultaneousdisappearing of the molecular signatures. State-ofthe-artRaman and synchrotron x-ray diffractionmeasurements on the temperature quenched sampleshow the amorphous character of this material. Thecomparison with vibrational and diffraction patternsof amorphous silica and germania, shows that a-carbonia is homologous to those glasses. The staticstructure factor of a-CO2 has also been calculated byab initio techniques (Sandro Scandolo), reproducingthe main features of the experimental pattern.These findings do extend the scenario of archetypalnetwork-forming disordered systems such as a-silica,a-germania, a-Si and a-Ge, and water.References[1] M.Santoro, F.Gorelli, G.Ruocco, R.Bini,S.Scandolo and W.Crichton, “Carbonia: theamorphous silicalike carbon dioxide” (in preparation)AuthorsM.Santoro (a,b), F.A.Gorelli (a,b), , G.Ruocco (a,d),R. Bini (b,e), S.Scandolo (f) and W.Crichton (g).(a) INFM-CRS-Soft Matter (CNR), Univ. la Sapienza.(b) LENS, Univ. di Firenze. (c) Dip. di Fisica, Univ. diFirenze. (d) Dip. Fisica, Univ. La Sapienza, Roma. (e)Dip. Chimica, Univ. di Firenze. (f) ICTP-DNSC,Trieste, Italy (g) ESRF, Grenoble, FranceInelastic scattering of X rays from overcriticalfluids at high pressureThe possibility of performing inelastic X rayscattering measurements on low Z materials in theDiamond Anvil Cell has been recently demonstratedwith an experiment on liquid water (Krisch et alPhys. Rev. Lett. 89, 125502 (2002)). We performedan inelastic X ray scattering experiment on ID 28beamline of ESRF on overcritical fluid Oxygen at highpressure using a Diamond Anvil Cell. As the criticaltemperature of Oxygen is about 155 K and weperformed the measurements at room temperature,it implies a value of T/T c equal to about 2. Wecollected data at about 1, 3 and 5 GPa and comparedthe sound velocity with the adiabatic one measuredby Abramson et al (J. Chem. Phys. 110, 10493(1999)). It results a positive dispersion of about 20%at all pressures which has never been reported for anovercritical fluid, and on the contrary it is an ordinarybehaviour of liquids.This result has been compared to previous data onNitrogen, Neon and Mercury indicating that themetastable extension of the liquid-vapourcoexistence line beyond the critical point splits the PTdiagram in two regions corresponding to twodifferent regimes for what concerns the positivedispersion.This experiment has to be followed by similar oneson under/overcritical fluids at high pressure in orderto better elucidate this result.AuthorsF.A.Gorelli (a,b), M.Santoro (a,b), G.Ruocco (a,d),T.Scopigno (a,d) and A. Beraud (e).(a) INFM-CRS-Soft Matter (CNR), Univ. la Sapienza.(b) LENS, Univ. di Firenze. (c) Dip. di Fisica, Univ. diFirenze. (d) Dip. Fisica, Univ. La Sapienza, Roma. (e)ESRF (Grenoble), France (f) ICTP-DNSC, Trieste.Phase diagram and vibrational spectroscopy ofpolymers at high pressurePolyethylene is the most widely used polymericmaterial but very little is known about its propertiesat high pressure. We performed an infraredabsorption and Raman scattering study ofpolyethylene at high pressure and temperatures inthe range 0-60 GPa e 300-650 K. We also performedan X ray diffraction experiment in the same PT rangein order to have structural information to couple tovibrational data. The whole data sets are alsocompared with simulations provided by a theoreticalgroup in Trieste (Sandro Scandolo, ICTP)AuthorsL.Fontana (a), M.Santoro (a,b), F.A.Gorelli (a,b),S.Scandolo (c), R. Bini (a,d) and M.Hanfland (e).(a) LENS, Univ. di Firenze. (b) INFM-CRS-Soft Matter(CNR), Univ. la Sapienza. (c) ICTP-DNSC, Trieste.(d) Dip. Chimica, Univ. di Firenze. (e) ESRF(Grenoble), France.SOFT Scientific Report 2004-0680

From Bulk to Nano-Structured LiquidsPhysical processes occurring at the microscopiclength scales are of fundamental importance inorder to understand the physical proprieties ofdisordered systems, either liquid or solid. Themacroscopic structural and transport phenomena,characterized by long lengths and slow dynamics,are intrinsically correlated with the physical eventstaking place at the microscopic scale, occurring atshort length and on fast time scale. The interplayand correlation between the micro (10 -6 m), or evennano (10 -9 m), phenomena and the macroscopic onehas been, and still it is, the basic problem in thedefinition of the disordered phase. This old andfundamental physical problem is rising recently newinterest for its relevance in the science andtechnology of Nano-Structured Disordered Matter(NSDM). We include in this name all theheterogeneous materials where a nano-structure ispresent but there is a long range disorder. In factany study or characterization of a NSDM undergoesto the previous outlined question: how this nanostructureaffects the macroscopic proprieties of thematter?A typical example of a NSDM are the colloidalsuspensions: these are composed by colloidalparticles, typically of sub-micro dimension, dispersein a solvent liquid. Each colloidal particle defines alocal nano-structure in the solvent liquid. OftenNSDM presents very peculiar proprieties, notpresent in standard bulk matters. For example,colloids show mechanical proprieties intermediatebetween the solid and the liquid one.Actually, a large variety of the NSDM (e.g. microemulsion,viscous and binary liquids, meso-phases)including also materials not properly soft (e.g.liquid-filled porous glasses, binary and complexglasses) are identified as soft matter.The disordered system group, present at LENS(DSG@LENS), during this year pursuits the researchon supercooled water and glass-formers, alreadyoutlined in the previous reports, in order to clarifythe open questions. Furthermore, DSG starts a newexperimental study of some NSDM by means oftime-resolved spectroscopy. In particular we selectthree classes of systems that are appropriate foroptical spectroscopy: liquid-filled porous glasses,micro-emulsions, and mixture of molecular liquidspresenting unexpected mesophases. All thesematerials present a definite local structure,characterized by a length scale of few nano-meters,and a long range disorder. Indeed, they showseveral modification of the macroscopic phenomenainduced by the static nano-structure, like phasediagrams and thermodynamic proprieties.The supercooled waterBetween the disordered materials, the supercooledand glassy water represents a very special case.Indeed, water is characterized by the anomalousbehavior of a number of physical properties. Theseanomalies become more and more marked in thesupercooled phase of water resulting in theunexpected temperature dependence of severaldynamic, transport and thermodynamic properties.This remarkable phenomenon is the sign of a strongLiquid-filled Porous Glassesc s [Km/s]1.601.551.501.451.401.351.301.251.20-30 -20 -10-40 -20 0 20 40 60 80 100Temperature [°C]Fig. 1. Here we report the sound velocity of waterobtained from the transient grating experiments (•)with the other data available in the literature. Inthe inset we report a magnification of the lowtemperature data, where it appears clearly theunexpected dispersion effect for ultrasonic data.variation in relevant features of the water structureand dynamics occurring at temperatures below themelting point. Despite the effort of researchers toelucidate this issue, many of its aspects still are tobe clarified. We have undertaken a series ofexperimental studies of supercooled water by meansof time-resolved non-linear spectroscopic techniques.With the ultra-fast optical Kerr effect spectroscopy(OKE) we have been able to measure the structuralrelaxation proprieties in an unprecedented timeinterval and data quality. We compared our data withthe main predictions of the mode-coupling theory(MCT). Our data substantially support the MCTscenario, providing unambiguous evidence thatweakly supercooled water can be described by a fullydynamic model successfully, with no need for athermodynamic origin. In order to complete thisresearch we are attempting to extend the OKEstudies on the water phase diagram. Furthermore westudied the acoustic and thermal phenomena in thesupercooled water dynamics by means of timeresolvedtransient grating experiments. In particular,acoustic phenomena in supercooled water showsseveral anomalous behaviours, as a steep decreaseof the adiabatic sound velocity and the possibleexistence of a negative dispersion (sound velocitywould decrease with increasing frequency) see fig. 1.References[1] R.Torre, P.Bartolini and R.Righini, Nature 248,296 (2004).[2] A. Taschin, P. Bartolini, M. Ricci and R. Torre,Philos. Mag. 84, 1471 (2004).[3] A.Taschin, P.Bartolini, R.Eramo and R.Torre.“Supercooled water relaxation dynamics byheterodyne transient grating experiment”, Phys.RevE, submitted.AuthorsP.Bartolini (a,b), R.Eramo (a,b), R.Righini (a,d) andR.Torre (a,b,c).(a) LENS, Univ. di Firenze.(b) INFM-CRS-Soft Matter(CNR), Univ. la Sapienza. (c) Dip. di Fisica, Univ. diFirenze. (d) Dip. di Chimica, Univ. di Firenze.81SOFT Scientific Report 2004-06

Scientific Report – Non Equilibrium Dynamics and ComplexityA porous glass (PG) is a usual silicate glass where ispresent a random network of empty pores. There aredifferent techniques to produce such porous glassesand the most common is based on sol-gel method.With this techniques it is possible to generate PGcharacterized by different porous shape anddimension distribution (see figure fig1). PG arecommercially available and they are known as VycorCCl 4, that it has been very well studied in its bulkphase. Our first investigation analyses two transportphenomena of the filled PG, in particular the acousticpropagation and the thermal diffusion, and comparethem with the same processes in bulk matter.Indeed the filled PG must be considered as twostrongly interacting materials, here the liquid andglass matrix, so that the transport phenomena coulddiffer substantially from the bulk one.References[1] A.Taschin, R.Cucini, P.Bartolini and R.Torre.“Acoustic propagation in liquid filled porous glasses,a test of Biot model”. In preparation (2006).AuthorsA.Taschin (a,c), R.Cucini (c), P.Bartolini (a,c) andR.Torre(a,b,c).(a) INFM-CRS-Soft (CNR), Univ. la Sapienza. (b) Dip.di Fisica, Univ. di Firenze. (c) LENS, Univ. di Firenze.Fig.2. In the figure we show a 3D computer modelof the porous glass structure. The empty pores andcavities have typical dimension of severalnanometers.Micro-emulsion: Water in OilMicro-emulsion is a colloidal suspension composed ofdrops of water stabilized by surfactant molecules in aoily solvent. Typically they have diameters of fewnano-meters and represent a soft dynamic nanostructure.In this soft matter example there are threecomponents, a solute (water) a solvent (oil) and astructuring agent (surfactant), that play a role indefining the local structure present in the materialand, furthermore, the long range disorder is dynamic.Thus in micro-emulsion the correlation between microand macro proprieties is more articulated than in thePG glasses, where only two interacting componentsare present and the disorder is static. We areperforming a series of time-resolved and frequencyspectroscopic experiments on a very well studiedFig.3. Here we report two experimental resultswith the relative fitting functions. The sample is aporous glass filled with a molecular liquid (CCl 4 inVycor 7030) and the data are obtained by means oftime resolved transient grating.(a trade mark from Corning Glass company): this PGshow a very narrow distribution of porous diametersaround 40 nm. PG can be easily filled with liquid ofdifferent nature and it represents a very useful solidmatrix to produce a static and rigid nano-structuringof the liquid. The porous glass filled with a liquid isindeed an interesting nano-structured disorderedmaterial, not only as a remarkable model for thebasic research on interaction at the nano scale butalso as effective example of many material presentin nature and in technological creation. We startfilling the Vycor glass with a simple molecular liquid,Fig. 4. A computer simulation of a inverse micellecharacterizing the AOT microemulsion. Only thesurfactant and water molecules are shown.micro-emulsion: the AOT-water-decane microemulsion,being AOT the surfactant and decane theoil. We focus on the investigation of acousticpropagation in this system as a function oftemperature, in order to measure and characterizethe interplay between the colloidal phase/structuremodifications and sound propagation. In particular weinvestigated the effect of the “percolation line”present in the phase diagram of this microemulsion(i.e. a supposed transition between two differentstates of dynamic aggregation), on the soundvelocity. Our preliminary results shown a weak effecton the elastic modulus of the dispersed phase (AOT-Water).SOFT Scientific Report 2004-0682

We found an increasing rigidity of micelles rising thetemperature over the percolation line.assigned to the existence of αCD/4MP complexes.Based on the crucial presence of a small amount ofwater, the transition is assigned to a rearrangementof hydrogen bonds, leading from a solvated αCD in4MP at lower temperatures to a regular network ofαCD molecules linked by water molecules at highertemperatures. The formed crystalline gel iscomposed of a fairly open regular structure of the4MP-αCD mixtureFig. 5. Here we show the light scattering data on AOTmicroemulsion, obtained by Sopra monochromator inbackscattering configuration (7.1 GHz), with theappropriate fitting function.signal HD-TG (a.u.)pure 4MP solventsound velocity (km/s)1,91,81,71,61,51,44MPαCD-4MPliquidphase1,3-40 -20 0 20 40 60Temperature (°C)solidphaseReferences[1] C.Ziparo, R.Eramo, I.Malfanti, C.M.C.Gambi andR.Torre. “Acoustic phenomena in AOT microemulsionsby frequency and time-resolved opticalspectroscopy”, in preparation.AuthorsR.Eramo (a,b), C.Ziparo (a,d), I.Malfanti (b,c),C.M.C.Gambi (a,c) and R.Torre (a,b,c). (a) INFM-CRS-Soft (CNR), Univ. la Sapienza. (b) LENS, Univ.di Firenze. (c) Dip. di Fisica, Univ. di Firenze.Freezing on heatingUnder the title “Freezing on heating” was recentlyreported the unexpected solidification upon heatingof a solution of a-cyclodextrine(αCD), 4methylpyridine (4MP) and water [1]. The solution ishomogeneous and transparent at ambienttemperature, and forms a milky white solid whenheated to temperatures between 45° and 75°. Thisprocess is fully reversible, on cooling the solid meltsand the original homogeneous solution is recovered.The role of water is essential, as demonstrated bythe incomplete solidification of samples withoutaddition of water (ca. 10mg/ml). A major argumentfor the explanation of the phase transition is thenegative solubility of the αCD in 4MP, that dropsnearly vertically around 75°C, or at lowertemperature when more water is added to thesolution [2]. Diverse experimental techniques havebeen used to characterize the liquid and solid phasesof the mixture, and the mechanisms driving thisunusual phase transition. X-Ray diffraction showedthat the solid phase is crystalline, and undergoesseveral phase transitions between 60 and 100°C.The lowest temperature phase is metastable, but 4other are stable and reversible with large hysteresisin temperature. Two of the transitions are alsoobserved in DSC measurements. Quasi elasticneutron scattering indicates that the dynamics of thecyclodextrine in the solid phase slows down (> 500ps) while a large part of the solvent stays liquid overthe whole temperature range, moving oncharacteristic timescales of ps. In the liquid phase isalso detected a motion slower than the solvent itself,1E-8 1E-7 1E-6 1E-5time (seconds)Fig. 6. HD-TG signal of the pure solvent and of themixture, at room temperature. The right part of thefigure shows the variation of the sound velocity inthe αCD/4MP solution, that tends to join the 4MPbehavior when increases the temperature,extrapolated (solid line) from experimental points(square).αCD molecules, the remaining space being filled with4MP molecules, which remain partially mobile. In atypical solution of 300 mg/ml of αCD in 4MP, withca.10mg/ml of water added, the solid phase isformed of crystallites of 5 to 30 micron length,surrounded by liquid solvent. Acoustic studies,through Transient Grating spectroscopy, probedirectly the viscoelastic properties of the solution.We therefore started to investigate structuralchanges in the liquid and pre transitional effectsusing this technique. The reorganization of thecomplex αCD/4MP could be responsible for thenegative solubility, by undergoing a change in itsstructure to which TG measurements will besensitive. A first comparison of the propagation ofthe acoustic wave in the pure solvent and αCD/4MPmixture exhibit very different behavior of bothsamples at room temperature (see on figure 6),difference that increases when the temperaturedecreases. Using the property that the solid phaseforms slowly (ca. 30 min), pre-transitional effectswere investigated at fixed temperature (following atemperature jump) by measurements at variousincreasing times: no change was observed in thedynamics of the liquid approaching the solidification.The system transforms directly from the solvatedαCD in 4MP into the crystalline phase. Preliminarymeasurements have been performed in the hightemperature phase (mixed liquid and solid). Onfigure 6 is shown the behavior of the sound velocityin the pure 4MP and the αCD/4MP solution: the liquidpart of the sample tends to join the pure 4MPbehavior. Surprisingly, the sound wave is notaffected by the solid phase, how can be expectedfrom this media presenting heterogeneities on themicrometer scale.83SOFT Scientific Report 2004-06

Scientific Report – Non Equilibrium Dynamics and ComplexityReferences[1] M. Plazanet, C. Floare, M.R. Johnson, R.Schweins, H.P. Trommsdorff, J. Chem. Phys. 121,5031 (2004).[2] M.Plazanet, M.Dean, M.Merlini, A.Hüller,H.Emerich, C. Meneghini, M.R. Johnson andH.P.Trommsdorff, “Heat induced crystallization andcomplex phase behavior of α-cyclodextrin solutions”,JACS, submitted.AuthorsM.Plazanet (a,b), P.Bartolini (a,b), A.Taschin (a,b)and R. Torre (a,b,c).(a) INFM-CRS-Soft (CNR), Univ.la Sapienza.(b) LENS , Univ. di Firenze. (c) Dip. di Fisica, Univ. diFirenze.Aqueous micellar solutionsA new Dielectric Spectroscopy technique wasdeveloped in the frequency range 30 MHz - 3 GHz.The complex permittivity of liquids is measured intransmission lines by a Vector Network Analyzer bydifferential methods. Two coaxial line cells weredone, differing for the length, and measured emptyand filled by the sample.This method gives "absolute measurements". Nocalibration by standard liquids is required. The cellshave to be machined with precision of 0.05 mm.Aqueous micellar solutions have been studied atconstant temperature and pressure. The sodiumdodecyl sulphate micellar solutions in the range 30mM - 520 mM were studied by three models, SingleDebye, Cole-Cole and Double Debye. The Cole-Coleand Double Debye models lead to know therelaxation time and the dielectric constant stepamplitude of the relaxation processes of the system.Two processes related to the micelle and to theinterfacial water have been shown with stepamplitudes from 10 to 30 vs. concentration andrelaxation times from 800 ps to 500 ps for themicelles, and step amplitudes from 1 to 12 vs.concentration and relaxation times practicallyconstant 110 ps for the interfacial water. The resultshave been tested by the Grosse's model for thedielectric constant and by the Kallay's model for theconductivity, taking into account the parametersobtained by small-angle neutron scattering, SANS,radius of the micelle, interfacial layer, fractionalionization and aggregation number.We are working on new fluorinated compounds bySolexis-Solvay that lead to ionic micellar solutions inwater. SANS measurements have been performed todefine the microstructure of the system as a functionof the surfactant counterion. Shape and dimension ofthe micelles as well as the parameters of theinteraction potential between micelles have beenevaluated for the ammonium, potassium, lithium,cesium and diethanol ammonium, having differentvolumes.The micelles interaction is due to hard sphere plusrepulsive Coulomb screened potential: Debye'slength and contact potential. As a function ofconcentration, temperature and counterion, themicelles can be spherical or ellipsoidal.Increasing the surfactant concentration, the micellegrow changes vs the volume increase, i.e. themicelle ionization degree decreases and the axialratio increase from 1.6 to 4.2 whereas the interfacialFig.7. The real and imaginary parts of the complexdielectric constant for water and sodium dodecylsulphate aqueous micellar solutions at differentsurfactant concentrations.layer is constant 0.4 nm. The detailed structure isknown for the micelles, included the area per polarhead. These results are very important for manyapplications. Since 2004, the study of a portion of agiant multidomain protein from vertebrate muscles insolution, the β-connectin, is performed by DynamicLight Scattering (DLS). We are comparing AtomicForce Measurements on single molecule performedby a CNR - ISC group with DLS resultsReferencesLeandro Lanzi, M.Carla', C.M.C.Gambi and LeonardoLanzi, J. of Non – Cryst. Solids 351, 2864 (2005).C.M.C. Gambi, R. Giordano, A. Chittofrati, R. Pieri, P.Baglioni; and Teixeira J.J. Phys.Chem. B 109, 8592(2005).AuthorsL.Lanzi (a,b), S.Marchetti (a,b) and C.M.C.Gambi(a,b).(a) INFM-CRS-Soft Matter (CNR), Univ. la Sapienza.(b) Dip. di Fisica, Univ. di Firenze.SOFT Scientific Report 2004-0684

Biopolymer-Vescicle InteractionsLarge interest is devoted to clarify the behavior ofcolloid systems composed by proteins (or DNA) andsurfactant-based vesicles. [1] Catanionic ones (anacronym derived from the term [cationic + anionic])are studied in more detail. [2] Such vesicles, VES, areeasily prepared and are a valid alternative toliposomes as carriers in gene therapy. They arethermodynamically and kinetically stable. Their layeris similar to biological membranes and allowsencapsulating hydrophilic and hydrophobicmolecules. Many properties of catanionic vesicles,such as their surface charge density, double layerfluidity, etc., can be properly tuned. Suchpossibilities ensure their use in bio-chemicallyrelevant methods.It is important to define which driving forcesinfluences the interaction process between VES andDNA, or proteins. Object of this research line is tounderstand the mechanisms responsible for theformation of vesicle-protein complexes, termed lipoplexes.Studies reported so far are based on TEM[3](Cryo-TEM) or fluorescence microscopy. Noinformation on the parameters controlling theinteraction processes, i.e. the charge density and theiso-electric point of the complexes, can be obtainedfrom the above techniques. The driving forcecontrolling biopolymer-vesicle interactions iselectrostatic, and the thickness of the electricaldouble layer around biopolymers, vesicles and theircomplexes is significantly affected from theinteractions. The surface charge density and somerelated quantities may be significantly modified. Todetect polarization effects and modifications in theelectrical double layer around such charged particles,CONTIN distribution function of the vesicles size,expressed as normalized intensity (in arbitraryunits) vs. the particle diameter, R H (nm) in 6.0mmol l -1 , mole ratio [1.7/1.0], SDS-CTAB catanionicmixtures, up, in the same system with 0.14 mmoll -1 added LYS, medium, and with 1.4 mmol l -1 LYS,down, at 20.0 °C.Dielectric relaxation spectra, reported as ε vs.applied frequency in the SDS-CTAB vesiculardispersion [6.0 mmol l -1 and 1.7/1.0 mole ratio], ○,for 0.42, ◊, 0.82, □, and 1.40, ∆, mmol l -1 LYS in thevesicular pseudo-solvent, at 20.0 °C.Dielectric Relaxation Spectroscopy (DS),Electrophoretic mobility and ζ-potential (ζ-P) areused.They allow to characterize in detail the interactionprocesses and give information on the chargedistribution around vesicles, proteins, DNA and theirlipo-plexes. Dynamic Light Scattering (DLS), andCircular Dichroism (CD) are also used. The firstmethod estimates the average size of the vesiclesand lipo-plexes formed upon interaction withbiopolymers, the second gives information on theconformation of the biomacromolecules bound ontovesicles.Vesicles formed by SDS and CTAB are used. They arenegatively charged, i.e. the SDS content is in excesswith respect to CTAB. Hence, interactions withproteins having high iso-electric point, such aslysozyme, LYS, may be experienced. The behavior ofmixtures containing SDS-CTAB based negativelychargedvesicles in the presence of increasingamounts of LYS is under study. The interactionprocess continues up to complete saturation of theavailable binding sites onto the vesicles and theprotein release from vesicles is demonstrated.References1- Zuber, G., Dauty, E., Nothisen, M., Belguise, P.,Behr, J.P. Adv. Drug Delivery Rev., 52, 245, (2001).2- Marques, E.F., Regev, O., Khan, A., Lindman, B.Adv. Colloid Interface Sci.,100-102, 83 (2003).3- Mel’nikova, Y.S., Lindman, B. Langmuir, 16, 5871(2000).AuthorsAdalberto Bonincontro 1 and Camillo La Mesa 21Dipartimento di Fisica; 2 Dipartimento di ChimicaUniversità di Roma “La Sapienza”85SOFT Scientific Report 2004-06

Scientific Report – Self Assembly, Clustering, Structural arrestPolyelectrolyte-Charged Liposome Complexes: Evidence ofEquilibrium Multi-Compartment AggregatesAggregation of colloidal particles induced byoppositely charged polyions has been extensivelyinvestigated both theoretically and experimentally,owing to its importance in many field of physicalchemistry. Recently, these phenomena attractedrenewed interest because the properties of theresulting aggregates, combined with thecharacteristics of self-organi-zation of the process,possess high potential for applications in materialresearch and bio-nanotechnologies. Among thesestructures, cationic lipid-DNA complexes havewitnessed of an increasing acceptance as preferentialDNA delivery vehicles in gene therapy [1], since theirFig. 1. Top: The average radius of the aggregatesfrom DLS measurements (o) reaches its maximumat the point of charged inversion, as measured by ζ-potential (o), i.e. at ζ=0.Bottom: a): TEM image of a typical pd-liposomeaggregate. Contrast is obtained mixing liposomesprepared loading their acqueous core with twodifferent concentrations of CsCl. “Heavily” and“lightly” loaded globules are clearly distinguished.b): Cs elemental map for the same frame, obtainedby filtering the transmitted electrons in an energywindow characte-ristic of the Cs-M 4,5 edge. c): theoriginal image a) and the map b) with a threshold at≈ 50% of the peak value are superimposed.enhanced permeability through the membranebilayer favors the delivery of DNA into the cells.“Columnar” (stacks of alternate planar layers of lipidand polymer) or “hexagonal” (lipids in the hexagonalphase H II with a DNA chain filling each honey-combcell) structures that form in these systems close tothe isoelectric point (where the stoichiometric chargeof DNA counterbalances the stoichiometric charge ofthe lipid phase) have been described [2].However, by means of the combined use of DynamicLight Scattering (DLS) and Transmission ElectronMicroscopy (TEM) measurements, we pro-vide astrong and direct evidence for the existence, in thepolyion-induced liposome aggregation, of anequilibrium cluster phase where liposomes maintaintheir integrity, with the ability of preserving theaqueous content of their core from the externalmedium. Oppositly charged polyelectrolytes stick tothe liposome surface and, with the increasingpolymer/lipid charge concentration ratio, ξ, theoverall electric charge of these “polyelectrolytedecoratedliposomes” (pd-liposomes) decreases,passing through the zero (isoelectric point) andreaching large negative values when polyions are inexcess (“overcharging” or charge inversion).Maximum aggregation occurs close to the point ofcharge inversion. As we have recently shown, theseclusters are equilibrium aggregates [3,4].Aggregation is due to a balance of long range electrostaticrepulsion and of short-range attraction,arising from the correlated adsorption of polyions atthe liposome surface ("charge patch" attraction).This cluster phase shows very interesting features inview of possible biomedical applications since thestructure of the aggregates, with liposomesreversibly "glued together" by a non-uniformdistribution of adsorbed polyelectrolytes, could findinteresting applications as "multi-compartmentliposomal aggregates" for controlled-release drugdelivery.References[1] D. Ferber, Science, 294, 1638 (2001).[2] I. Koltover, T. Salditt, J. O. Rädler, C. R. Safnya,Science, 281, 78 (1998).[3] F. Bordi, C. Cametti, M. Diociaiuti, S. Sennato,Phys. Rev. E, 71, 050401(Rd) (2005).[4] F.Bordi, C.Cametti, M.Diociaiuti, S.Sennato,Biophys. J. 2006, 91,1513-1520AuthorsF. Bordi § , C. Cametti § , S. Sennato § , M. Diociaiuti #§Dipartimento di Fisica, Università di Roma ″LaSapienza″, Roma and INFM CRS-SOFT#Dipartimento di Tecnologie e Salute, IstitutoSuperiore di Sanità, Roma.SOFT Scientific Report 2004-0686

Dielectric Properties of Polyelectrolyte Aqueous Solutions:the Scaling ApproachPolyelectrolytes are macromolecules with manyionizable groups. In polar solvents, these groups candissociate, leaving charges on the polymer chain andreleasing counterions in solution. Polyelectrolytesfind widespread applications as functional poly-mersin many industrial processes as thickeners,dispersants, ion-exchange resins, enhanced oilrecovery agents etc. Moreover, DNA and a variety ofbiologically important macromolecules arepolyelecrolytes. Their properties depend on thefraction of dissociated ionic groups, on the solventquality for the polymer backbone, the dielectricconstant of the solvent and the salt concentra-tion.Fig. 1. Top - Different chain conformations areobserved in the different concentration regimesand in different solvents. Bottom: Scalingbehaviour of the dielectric parameters as afunction of polymer concentration. a): theexpected exponent (α=1) for the “good solvent”model is retrieved using pure ethylene glycol (EG)as solvent, a good solvent for the polymeremployed; in contrast, the exponent α increasesabove 1 with the increase of the water content(poor solvent) in the mixture. b): the reversal isalso true: the expected exponent for a poorsolvent (1/3) is obtained for pure water solution.Long-range electrostatic interactions be-tweenpolyions and counterions and between dif-ferentcharged groups on the same polymer chainintroduces new scale lengths and the fine balancebetween long-range electrostatic and short-rangepolymer-solvent interactions gives rise to a com-plexphenomenology.We have recently investigated [1-3] the radio-wavedielectric behaviour of aqueous polyelectro-lytesolutions in the light of the scaling approachproposed by Dobrynin and Rubinstein [4], as afunction of the solvent quality and in differentconcentration regimes, showing how the differentpolyion conformations reflect on the low-frequen-cypermittivity and electrical conductivity.As can be seen in Fig. 1 a) and b), for the par-tiallycharged PMVP-Cl polymer dissolved in a mixedsolvent the predicted scaling behaviour is observedin a wide concentration range. For this polymer,water and ethylene glycol [EG] behave as poor andgood solvent, respectively, and in both cases apower law is clearly evidenced. In particular, whenthe data are analyzed according to the “good solventmodel” (Fig. 1 a), the expected value of theexponent in the polyion concentration dependenceα=1 is attained for X=1 (pure ethylene glycol), whilea progressive deviation is observed as the quality ofthe solvent changes, approaching the “poor solvent”,i.e., as the mole fraction of water is progressivelyincreased. Analogously, when the same data areanalyzed according to the “poor solvent model” (Fig.1 b), the expected value of the exponent α=1/3 isretrieved at X=0 (pure water), whereas deviationsare apparent when the EG con-centration in thesolution increases (good-solvent condition). Theobserved scaling behaviour of the dielectricproperties of polyelectrolytes in solvents of differentquality gives strong support to the existence of a“necklace” conformation of the chain, under poorsolvent condition.References[1] F.Bordi, C.Cametti, T.Gili, S.Sennato, S.Zuzzi,S.Dou, R.H.Colby, Phys. Rev. E 72, 031806 (2005).[2] F.Bordi, C.Cametti, T.Gili, S.Sennato, S.Zuzzi,S.Dou, R.H.Colby, Journal of Physical Chemistry122, 234906 (2005).[3] Bordi, C. Cametti, S. Sennato, S. Zuzzi, S. Dou,R. H. Colby, Phys Chem Chem Phys. 2006; 8:3653-3658[4] A. V. Dobrynin, M. Rubinstein, Prog. Polym. Sci.30, 1049 (2005).AuthorsF. Bordi § , C. Cametti § , S. Sennato § , S. Dou # , R. H.Colby #§Dip. di Fisica, Università di Roma ″La Sapienza″,Roma and INFM CRS-SOFT# Dept. of Material. Sci. and Engineering, ThePennsylvania State University, University Park, PA,USA.87SOFT Scientific Report 2004-06

Scientific Report – Self Assembly, Clustering, Structural arrestAging of dilute aqueous Laponite suspensions studied bymeans of 23 Na Triple-Quantum NMR spectroscopyDuring the last years a drastic change has takenplace in application and studies based on NuclearMagnetic Resonance (NMR), as a result of theavailability of high-field spectrometers and powerfulcomputers. As a consequence, a whole series of newmethods, such as multiple-quantum NMRspectroscopy, has risen. These methods haveproduced a qualitative change in NMR research byallowing dynamical studies in a way previouslyp b[%]τ c[ns]QCC [MHz]100959085807570656055503230282624222018160,800,750,700,650,600,550,501.2%1.4%0 50 100 150 200 250Correlation Time1.2 %1.4 %1.7 %2.0 %2.4 %2.8 %0 50 100 150 200 250t w[days]Slow DynamicsQuadrupolar Coupling Constant1.2 %1.4 %1.7 %2.0 %Slow Dynamics2.4 %2.8 %0 50 100 150 200 250t1.7%2.0%LCDaysBound 23 Na Counterions1.2% w/w1.4% w/w1.7% w/w2.0% w/wt w[days]HCFig. 1: (a) bound counterions, (b) correlationtime, (c) quadrupolar coupling constant, asfunction of aging time. (d) Schematic laponitesuspensions arrested phase at lowconcentration (LC) and at high concentrationabcdimpossible by standard NMR techniques based onsingle-quantum coherences.We set up a new NMR procedure based on standardrelaxation time measurements and advanced triplequantumsodium signal detection to monitoring agingin low density colloidal systems. This is obtained bymeans of measurements of NMR parameters fromwhich we extracted rotational correlation times τ c,quadrupolar coupling constant QCC and total amountof sodium ions involved in electrostatic screening(bound counterions concentration) p b to describecounterions dynamical properties.Laponite is composed of rigid disc-shaped crystalswith 1nm thickness and 30nm diameter. Each crystalis composed of roughly 1500 unit cells with anempirical chemical formula:Na + 0.7[(Si 8Mg 5.5Li 0.3)O 20(OH) 4] -0. 7.NMRmeasurements were performed on 23 Na nuclei usinga Bruker Avance 400 system with a 9.4 Tsuperconducting ultrashield magnet. Six laponitedispersion in water solution (D 2O+H 2O) have beenprepared at concentrations below the transitionisotropic liquid – isotropic gel (C w=1.2%, 1.4%,1.7%, 2.0%, 2.4%, 2.8% and I=10 -4 ).We monitored τ c, QCC and p b as function of agingtime (Figure 1). Our findings show that boundcounterions concentration, which determine theLaponite disks electrostatic screening length, plays afundamental role in the differentiation of the route togelation. Two important observations have beendone. First of all, arrested phase in isotropicsolutions have been observed. Furthermore,difference we observed in the way to reach thearrested phase as function of laponite concentration.At low concentrations (C w=1.2%, 1.4%, 1.7%) thearrested phase is due to the formation of clusters,while at high concentrations (C w=2.0%, 2.4%,2.8%) the single laponite platelets seems to be theelementary constituent of the entire system (Figure1). Thus, if for low concentrations we speak of acluster driven arrested phase achievement, as far ashigh concentrations is concerned a diskes networkdriven, arrested phase transition should be invoked.References[1] T. Gili, NMR Multiple Quantum Spectroscopy:application to the study of materials and biologicalsystems, PhD thesis, Università di Roma “LaSapienza”, novembre 2005.Authors:S. Capuani (a), T. Gili (b), B. Maraviglia (c).(a) INFM-CRS-SOFT (CNR), Dip. di Fisica, Univ. “LaSapienza”, Roma, Italy. (b) Centro Enrico Fermi, Dip.di Fisica Univ. “La Sapienza”, Roma Italy.(c) Dip. diFisica Univ. “La Sapienza”, Roma, Italy.SOFT Scientific Report 2004-0688

Clustering and Cooperative Dynamics in Reactive MixturesDisparate fluids can evolve into structurally arrestedstates, either of glass or gel type, with differentvariables serving as a control parameter [1]. Weconcentrate on the idea that clusters of correlatedparticles are at the basis of glass formation andinvestigate how the dynamics and clustering are, infact, intimately related [2, 3].Experimental studies providing evidence for aquantitative connection of this type are generallyprevented by the absence of direct access to relevantcluster properties in real systems. We have exploitedparticle clustering that occurs by stepwiseaggregation in a two-component reactive mixture(DGEBA-DETA N e:N a). Step polymerization is a selforganizationprocess able to generate permanentmolecular clusters similar in shape to the transientones observed in cooperativity studies. While theirgeometry and mass distribution depends on anumber of factors, their average size x n (i.e., theaverage number of monomers per molecule) turnsout to be only dependent on the functionality (i.e.,reactive groups per molecule) of the reagents andthe number of bonds created, according tox n(α)=1/(1-f α), where α is the chemical conversion,and f=2N e/(N e+N a) denotes the average functionalityof the system. Thus, knowing f for a given mixtureand measuring α by differential scanning calorimetry,enabled us to calculate the average size x n ofmolecular clusters making up the system at any timeof reaction. x n displays critical behavior at α=1/f.The structural dynamics of our reactive system wasmonitored throughout reaction by VH depolarizedphoton correlation spectroscopy, probing opticalanisotropy fluctuations, which arrest at the glasstransition. Instead, the technique is blind to theformation of a gel phase. The structural relaxationtime τ exhibits a strongly nonlinear dependence onα. Figure 1, showing logτ versus x n for differentreactions, reveals how the x n and the τ data,independently determined, relate to each other. Wefind that the x n dependence of τ is expressedremarkably well by an exponential law, that is,τ ∝ exp(Bx n). This means that the relaxation timediverges, determining a structurally arrested glassstate, when the average size of particle clustersbecomes infinite.The Adam-Gibbs model provides a convenientframework for interpreting our finding. One canargue that a monomer involved in a rearrangementis likely to take its bonded monomers along, so thatthe average number of particles in the system thatcooperate to move grows proportionally to x n. Thus,an exponential variation of τ with x n would beexpected, as we find to be the case.In conclusion, our data reveal the cluster propertyinvolved in the glasslike arrest and its quantitativelink with the structural relaxation time. We find thatincreasing the average size of clusters of bondedparticles causes the dynamics to slowdownprogressively in such a way that, differently fromgelation, an arrested glass state forms (τ→∞) whenx n diverges. The behavior of x n correlates to the sizeof the ‘cooperatively rearranging regions’ postulatedby the Adam-Gibbs model for glass forming liquids.These results have two implications. First, they bringout a major difference between the glass andgelation transitions in terms of the cluster propertywhich is relevant to the transition [2]: a glass resultswhen the average number of particles in a cluster(x n) tends to infinity; by contrast, the gelationtransition is known to occur when the weightaveragecluster size (x w) diverges due to theformation of the first particle network of macroscopicsize. Second, our findings suggest that the steppolymerization process generates clusters that,although they are of a non-transient nature, behavemuch like dynamical heterogeneities observed insupercooled liquids [3]. Their size, in particular,identifies a growing, diverging lengthscale associatedwith the cooperative dynamics of the system.2N e:N a1 10:35:25:2.804:310:9-1N a/N e0.2 0.4 0.6 0.8 1.0-21.00.9-3α 00.80.7-40.62 3 4 5 6 7 8 9 10xFig.1. Semilogarithmic plot n of the structuralrelaxation time τ, vs the average size x n of clustersgrown by polymerization, for five DGEBA-DETA N e:N acompositions as indicated. The data follow straightlines for more than five decades in τ. In the frame ofthe Adam-Gibbs model, an exponential variation of τwith x n, in a process at constant temperature,supports a direct relationship between x n and the sizeof the CRRs. In the inset: Dependence on the molarratio N a/N e between the reagents, of the values α 0 atwhich the τ data (directly analyzed as a function of α)tend to diverge. They match the expected variationof 1/f=[1+(N a/N e)]/2 (solid line).log 10τ(s)References[1] S. Corezzi, D. Fioretto, P. Rolla, Nature 420, 653(2002)[2] S. Corezzi, L. Palmieri, J.M. Kenny, D. Fioretto, J.Phys.: Condens. Matter 17, S3557 (2005)[3] S. Corezzi, D. Fioretto, J.M. Kenny, Phys. Rev.Lett. 94, 065702 (2005)Authors:S. Corezzi (a), D. Fioretto (b), and J.M. Kenny (c)(a) CRS-SOFT and Dipartimento di Fisica, Universitàdi Roma La Sapienza, Roma (Italy); (b) CRS-SOFTand Dipartimento di Fisica, Università di Perugia,Perugia (Italy); (c) Materials Engineering Center,Università di Perugia, Terni (Italy)89SOFT Scientific Report 2004-06

Scientific Report – Self Assembly, Clustering, Structural arrestRole of metal ions in protein aggregation processesAmyloidosis is a family of pathologies caused by thetransition of endogenous proteins and peptides fromthe physiological globular configuration to apathological fibrillar state. The term amyloidosisdescribes a heterogeneous group of diseases (morethan 20), which are characterized by extra-cellulardeposition of fibrillar material. Among them, theAlzheimer’s disease (AD) is a progressive anddevastating neurodegenerative pathology affectingan important fraction of the aged population in thedeveloped world. AD is characterized by memorydisorders, degradation of the personality and otherbehavioural abnormalities correlated to the loss ofneurons from cortex and hippocampus. These eventsare accompanied by peculiar morphologicalmanifestations like formation of senile plaques in thebrain, amyloidosis of brain vessels and intraneuronaldeposits of amyloid fibrils. The majorcomponent of the AD amyloid plaques are the β-amyloid peptides (Aβ). It has been observed thatplaques contain large amounts of transition metalslike Cu, Fe and Zn (the last one being the mostabundant). Their role is not yet fully understood, butit has been conjectured to be crucial in thepathological effects of AD. X-ray absorptionspectroscopy (XAS) can be profitably used forstructural studies on biological material [1-3], as thetechnique can be employed for samples in any stateof aggregation, in particular for proteins in solution,thus allowing investigations in physiologicalconditions. Owing to its chemical selectivity andsensitivity to the local atomic arrangement aroundthe absorber, one can get a clear-cut identification ofthe amino acid residues primarily bound to themetal. XAS has been used to investigate the localstructure around the ion in samples of Aβ-peptidescomplexed with Cu 2+ or Zn 2+ . Our data showdifferent metal binding site structures in β-amyloidpeptides according to whether they are complexedwith Cu 2+ or Zn 2+ ions. While the geometry aroundcopper is stably consistent with an intra-peptidebinding with three metal-coordinated Histidineresidues, the zinc coordination mode depends onspecific solution conditions. In particular, differentsample preparations are seen to lead to differentgeometries around the absorber that are compatiblewith either an intra- or an inter-peptide coordinationmode (fig. 1). This result reinforces the hypothesisthat assigns different physiological roles to the twometals, with Zn favoring peptide aggregation and, asa consequence, plaque formation. The human priona) b) c)Fig. 1: Schematic illustration of the structures of(Cu–Aβ) 1 (panel a), (Zn–Aβ) 1 (panel b) and (Zn–Aβ) 2(panel c), as they emerge from the fit to the data.Only metal–Histidine bonds are explicitly shown. TheAβ-peptide backbone is drawn as a shoe string (fromRef. [3])protein binds Cu 2+ ions in the octarepeat domain ofthe N-terminal tail up to full occupancy at pH=7.4.Recent experiments show that the HGGG octarepeatsub-domain is responsible for holding the metalbound in a square planar configuration. On thenumerical side [4-6], we have approached a similarproblem which has to do with cellular prion protein(PrP c ). PrP c is a cell surface glycoprotein that isconsidered a key molecule for the understanding ofthe development of a group of neuro-degenerativediseases, generically referred to as “prion diseases”.Prion diseases are characterized by theconformational transition of the native,predominantly α-helical, PrP c , into a pathogenic,mostlyβ-sheet,conformer called scrapie,PrP Sc .The human prion proteinbinds Cu 2+ ions in theoctarepeat domain of theN-terminal tail up to fulloccupancy at pH=7.4.Recent experiments showthat the HGGG octarepeatsub-domain is responsible for holding the metalbound in a square planar configuration. By using firstprinciple ab initio molecular dynamics simulations ofthe Car-Parrinello type, we have investigated thecoordination of Cu to the binding sites of the prionprotein octarepeat region [7]. Simulations arecarried out for the complexes Cu(HGGGW)(wat),Cu(HGGG) and [Cu(HGGG)] 2. While the presence ofa Trp residue and a water molecule does not affectthe nature of the Cu coordination, high stability ofthe bond between Cu and the amide nitrogen ofdeprotonated Gly’s is confirmed in all cases. For themore interesting [Cu(HGGG)] 2 complex adynamically entangled arrangement of the twodomains with exchange of amide nitrogen bondsbetween the two Cu centers emerges (fig. 2), whichis consistent with the short Cu-Cu distance observedin experiments at full Cu occupancy.Fig. 2: Structure of the [Cu(HG − G − G)] 2 systemobtained in the (spin-restricted simulation) atT=300 K and at t=0.86 ps (from Ref. [7])References[1] S.Morante, et al., J. Biol. Chem. 279, 11753(2004).[2] M.Benfatto, et al., Biophys. Chem. 110, 191(2004).[3] F.Stellato, et al., Eur. Biophys. J. 35(4), 340(2006).[4] G. La Penna, et al., Int. J. Mod. Phys. C 15, 205(2004).[5] G.La Penna, et al., J. Chem. Phys. 121, 10725(2004).[6] S.Morante, et al., J. Chem. Phys. 125. 034101(2006)AuthorsF. Guerrieri (a, c), V. Minicozzi (a), S. Morante (a, b, c),G. C. Rossi (a, c), F. Stellato (a, c)(a) Dip. di Fisica, Univ. di Roma Tor Vergata, Roma II(b) CRS SOFT-INFM-CNR, Roma, Italy(c) INFN, Sez. di Roma Tor VergataSOFT Scientific Report 2004-0690

Role of water around biomolecules and surfactantsIn solution the mutual interactions between solutesand solvents define all the conformation anddynamical properties, as well as the deviation of thesolvent from its pure state. Our work is devoted tothe analysis of these interactions, both withexperiments and Molecular Dynamics simulations, inaqueous solutions of biopolymers and surfactants.Network of vicinal water around C 12E 6 surfactant.We analysed the solute-water interactions in proteinsbelonging to organisms living at ambienttemperature, named mesophiles, or extremetemperatures, even exceeding the boilingtemperature of water, named thermophiles. Up tonow a satisfactory explanation on the origins ofadaptation at extreme conditions is still lacking. Therelated scenario depends on many independentfactors, the amino acidic primary sequence, thetypes of amino acids exposed to the solvent, i.e. thesecondary and tertiary structure, the morphologyand energetics of the interfacial region. Wesimulated the thermal response of two proteinshaving a high homology in the primary structure, theG-domain of the Elongation Factor of Escherichia coli(mesophilic) and Thermus thermophilus (moderatelythermophilic) with denaturation temperaturesdiffering by about 15 K. Our studies showed thatunfolding in the mesophile is preceded by anenhanced exchange of interfacial water moleculeswith the bulk, accompanied by concomitantabsorption of heat by hydrophilic aminoacids [1].Pertaining the comparative study of mesophilic andthermophilic counterparts, and notwithstanding thesame hydrophobic/hydrophilic composition, the moststriking result regards the high efficiency of thethermophile in adsorbing water molecules, inparticular at high temperature and the largerhydrophilic character of the thermophile [2]. Thedata support the notion that water is an ambivalentelement, destabilizing proteins due to its efficiency inhydrogen bonding and acting as a bio-protectantwith respect to thermal or mechanical stress. Asuggestive interpretation is that the strategydeveloped by thermophilic species to defend againsttemperature and, indirectly, water flooding theprotein core, is to allow for a small, but significantportion of water molecules to partially penetrate theprotein-water interface.Solutions of non-ionic surfactants were investigatedby looking at the molar volumetry andcompressibility as a function of temperature andconcentration. The results allowed the determinationof the hydration state and its temperaturedependence [3]. The visco-elastic response wasrevealed at high concentration and an extracontribution to the compressibility at lowconcentration, probably due to water exchange [4].To understand the microscopic origin of suchbehaviour we performed Molecular DynamicSimulation on C 12E 6 spherical micelle. The resultsindicated that: 1) dehydration occurs mainly on theoil core exposed surface [5]; 2) water moleculesaround the oil core form H-bound clusters whose sizeand distribution change with temperature; 3) in thisregion the water cluster have the largest size [6].The diffusion of water close to biological materialsdoes not grow linearly in time, as expected by thebrownian motion. The onset of spatial and temporalcorrelations, arising from the heterogeneity of theexposed, is usually invoked to explain thisphenomenon. Our simulations of water confined by amodel membrane showed that the dynamics can befairly well described by a simple brownian model withan effective diffusion coefficient [7]. Longitudinaldiffusion follows a standard behavior whereas theeffect of confinement manifests itself in mixing thelongitudinal and transversal dynamics. The essenceof the process has been captured by our simplifiedapproach which covers a considerably large timeinterval.References[1] S. Melchionna, G. Briganti, P. Londei, P.Cammarano, Phys.Rev.Lett., 92, 158101 (2004).[2] S.Melchionna, R.Sinibaldi, G.Briganti, Biophys. J.90, 4204 (2004).[3] G. Briganti, M. Maccarini, G. D’Arrigo Journal ofPhysical Chemistry B,108, 4039 (2004).[4] G. D’Arrigo, G. Briganti, M. Maccarini, Journal ofPhysical Chemistry B,110, 4612 (2006).[5] F. Sterpone, C. Pierleoni, G. Briganti, M. Marchi,Langmuir 20, 4311 (2004).[6] F. Sterpone, C. Pierleoni, G. Briganti, M. Marchi,Journal of Physical Chemistry B,110, 18254 (2006).[7] M. Sega, R. Vallauri, S. Melchionna, Phys. Rev. E72, 041201 (2005).Authors:S. Melchionna (a), G. Briganti (a), P. Londei (b), P.Cammarano (b), R.Sinibaldi (c), M. Sega (d), R.Vallauri (d), C. Pierleoni (e), F. Sterpone (f), M.Marchi (g), M. Maccarini (h), G. D’Arrigo (i).(a) CRS-SOFT, Department of Physics, University “LaSapienza” (Rome, Italy), (b) Department of MedicalBiochemical and Biological Medicine, University “LaSapienza” (Rome, Italy), (c) Department of AppliedScience, “Politecnico delle Marche” (Ancona, Italy),(d) Department of Physics, University of Trento(Italy), (e) Department of Physics, University ofL’Aquila (Italy), (f) Department of Chemistry,University of Texas (USA) (g) Centre d’etudes Saclay(France), (h) Institut fϋr physikalische chemie(Heidelberg, Germany), (i) Department of Energetic,University “La Sapienza” (Rome, Italy)91SOFT Scientific Report 2004-06

Scientific Report – Self Assembly, Clustering, Structural arrestMulti-Scale Simulations of Macromolecular SystemsMathematical modelling and computer simulation ofmacromolecular and biological systems is in a stageof burgeoning progress. Such systems raisenonetheless a great challenge to computationalscientists, mostly on account of the wide anddisparate range of spatio-temporal scales involved intheir dynamical evolution. Typically both problemsinvolve space and time-scale separation calling formulti-scale modelling and proper theoreticalmethodologies derived from statistical mechanics.We tackle the problem with two distinct strategies. Afirst approach, typically applied to colloidal andbiological polymers, is based on a multi-scaleseparation between degrees of freedom, namelyheavy solutes in presence of a light surroundingsolvent. The solvent hydrodynamics is treated at thelevel of the lattice Boltzmann method while thesolutes are treated by means of Molecular Dynamics.The connection between the two descriptions isestablished by introducing thermal noise in theframework of fluctuating hydrodynamics and by amomentum balance technique [1]. Alternatively, wehave developed a numerical scheme to directly solvethe time-dependent Fokker-Planck equation in orderto account for the liquid state of the solvent at thelevel of the collision operators [2]. Our secondstrategy focuses on rare events and complex freeenergylandscapes. The goal here is to reduce thetemporal diversity (restriction of internal modes,spectrum compression, and similar techniques) andartificially induce the process under study (the socalledrare event) in order to investigate itsspontaneous evolution. The two approachesdeveloped in our group are the so-called Blue MoonEnsemble [3] and Mass Rescaling [4] which eitherintroduce a constraint to explore the veryunprobable regions of phase space or alter thevisiting frequency of the low probability regions.Our laboratory is specialized in large-scale simulationof complex systems by developing innovativeFig.1: Transition path of Alanine dipeptide inducedby enhanced conformational sampling.numerical techniques. In the past years we havedeveloped an open-source simulation platformnamed DLPROTEIN which allows for parallel andcross-platform simulation of complex macromolecularsystems [5]. The inclusion of multi-scalemethods into the package is currently in progress.Hydration states is a major actor in stabilizingproteins in aqueous environments. A particularlyinteresting class of proteins are the thermophilicones, which, in contrast to the mesophilic variants,present a smaller heat capacity upon unfolding. Inout studies we have found that the water-exposedsurface area is larger for the thermophile, probablydue to a peculiar corrugation of the exposed surfaceof this species with a larger number of intramolecular hydrogen bonds, stronger electrostaticinteractions and a flatter free energy landscape. Thiswork suggest that the specific hydration stateenhances macromolecular fluctuations but, at thesame time, increases thermal stability [6].Biomolecules embedded in sugar matrices canovercome adverse conditions such as dehydrationand/or high temperatures. Among sugars, trehalosehas been found the most effective protectant.Notwithstanding the large attention devoted, thetrehalose peculiarity is still poorly understood.Experiments show how the size and the hydrogenbonding capability of different saccharides affectprotein dynamics and the protein-matrix coupling ina subtle way. MD simulations have been performedon carboxy myoglobin/water/saccharide (trehalose,sucrose, maltose, glucose) systems. Atomicfluctuations, heme pocket structures, protein-solventhydrogen bonding have been analyzed and compared[7]. Results suggest the action of saccharides be dueto protein-water-sugar interactions via the presenceof interfacial structures containing excess water withrespect to the bulk, and few sugar molecules boundto protein via single hydrogen bonds,in agreementwith the "preferential hydration model".References[1] M. Fyta, S. Melchionna, S. Succi, E. Kaxiras, inpreparation.[2] S. Melchionna, S. Succi, J.-P. Hansen, Intl. J.Mod. Phys. (2006), in press.[3] E.A.Carter, G.Ciccotti, J.T.Hynes, R. Kapral,Chem.Phys.Lett. 156, 472 (1989).[4] S.Melchionna, Phys.Rev.E 62, 8762 (2000).[5] http://www.sissa.it/cm/DLPROTEIN.[6] S. Melchionna, G. Briganti, R. Sinibaldi, Biophys.J. (2006) in press.[7] G. Cottone, S. Giuffrida, G. Ciccotti, L. Cordone,Proteins 59, 291 (2005).AuthorsS. Melchionna, G. CiccottiSOFT-INFM, Dipartimento di Fisica, Università diRoma La Sapienza.SOFT Scientific Report 2004-0692

Investigation of the Relation Between Local InherentStructures Properties and the Diffusivity: the Role ofFluctuations in Supercooled Liquids DynamicsSupercooled liquids are characterized by dynamicswhich take place on at least two well-separated timescales: a fast microscopic dynamics (associated toatomic or molecular motions at fixed liquid structure)and a slow structural relaxation time (which requiresstructural changes and diffusion processes). In thelatest years many efforts have been made toelucidate the physics of supercooled liquids. Thetime separation between the two mechanismscontrolling the physics of supercooled liquids allowsthe development of a thermodynamic approachbased on the analysis of the potential energy surface(PES) geometry. At sufficiently low temperatures,the motion of the system can be separated intomotion confined in one PES basin (on the short timescale), and interbasin motion (on the long timescale). The study of the PES of simple models, aidedby the increased computational resources, hasprovided important insights into the mechanismscontrolling the slowing down of dynamics on coolingand the PES approach has become a powerfulformalism for the analysis of the low temperaturephysics, strongly supporting the reasonable hopethat in supercooled states structural properties areconnected to dynamics.In our work we go one step further performing adetailed study of thousands independent equilibriumtrajectories for two models for supercooled liquids:a system of 216 molecules of water interacting via atwo body potential (SPC/E) and a Kob-AndersenLennard Jones system of 155 atoms. Due to the highnumber of analyzed trajectories and to the smallsystems size we could perform a careful study offluctuating quantities. We focus on the relationbetween supercooled liquids dynamics and PESproperties and we separate in a model-free approachthe role of temperature and the role of the exploredpotential energy landscape basin depth (eIS)I inthe particle dynamics, as shown in the fig. 1. Weidentify the connection between diffusioncoefficients on the depth of the local potentialenergy minima explored. We express the averagediffusion coefficient for the system as a sum overcontributions of the sampled basins, establishing amodel unbiased connection betweenthermodynamics and dynamics in the potentialenergy to landscape framework. Moreover, ourstudy allows to clarify the role played by fluctuationsof static and dynamic properties in the slowing downof the dynamics of liquids, providing aninterpretation within the energy landscape picturefor the presence of dynamical heterogeneities andconnecting the peculiar dynamical behavior observedin supercooled states to the observed non-linearityin the relation between local diffusion and basindepth.Refences[1] E. La Nave and F. Sciortino, J. Chem. Phys. B108, 19663 (2004).[2] E. La Nave, S. Sastry and F. Sciortino, submittedto PRL (2006) and cond-mat/0512729 (2005).Fig. 1. Top Panel: Diffusivity D as a function of eISfor a Lennard-Jones system. Each point representan independent trajectory. The diffusivity is afunction of both T and eIS. Lower Panel: Same datawhere the role of temperature is sorted outrescaling D by the correct function.AuthorsE. La Nave (1), S. Sastry(2) and F. Sciortino (1)(1) Dipartimento di Fisica and INFM-CNR Udr andCRS-SOFT: Complex Dynamics in StructuredSystems, Universita' di Roma ``La Sapienza'',Piazzale Aldo Moro 2, I-00185, Roma, Italy.(2) Jawaharlal Nehru Centre for Advanced ScientificResearch, Jakkur campus, Bangalore - 500064,India.93SOFT Scientific Report 2004-06

Scientific Report – Self Assembly, Clustering, Structural arrestCoil-Globule Transition of DNA Molecules Induced byCationic SurfactantsCompaction of DNA induced by cationic surfactantshave attracted in the recent years a large amount ofinterest due to its importance both in technologicaland biomedical applications, particularly for thepotential use of these systems as vehicles for genedelivery and gene transfection. One of limitingfactors for gene therapy is the DNA transport, since,under normal physiological condition, DNA is a highlycharged polyion that is repelled by the similarlynegative cell membrane.In the complexation between DNA and cationicspecies, the effective negative charge of DNA islowered, allowing the complex to approach thecharged cell membrane. In addition, it has beenshown that cationic surfactants collapse individualDNA molecules and lead to small particles allowingan efficient internalization of these complexes intothe cells. In relation to this, the DNA inchromosomes was found to be in a highly condensedstate in comparison with the free DNA in thesolution.A wide variety of physical methods have beenapplied to the study of DNA-surfactant interactionsand recently these interactions have been alsostudied at the single-molecule level, with the use ofa fluorescent microscopy technique [1,2].It has been found that isolated DNA chains undergoa discrete coil-globule transition by the addition ofcationic surfactants, with a region where coil andglobule form coexist for intermediate concentrationof amphiphile. The molecular mechanism leading tothis conformational change has been described asfollows. Cationic surfactants interact with DNA by acombination of initial electrostatic interactionfollowed by a cooperative binding of surfactantligands to the same DNA molecule, driven byhydrophobic forces. The coexistence of DNAmolecules with different conformation has only beenobserved, to our knowledge, by fluorescencemicroscopy.Recently, we used dynamic light scattering [3] anddielectric spectroscopy [4] to investigate thecompaction of DNA induced by two simple modelamphiphiles, cetyltrimethylammonium bromide(CTAB), a single chain cationic surfactant, anddodecyldimethylamine oxide (DDAO), which cancoexist in either non ionic or cationic form,depending on pH. The behaviour of thehydrodynamic radius and the size distribution of theDNA-surfactant complexes have been studieddirectly by dynamic light scattering, evidencing abimodal distribution with the simultaneous presenceof coil and compact globule state, whose relativeconcentration changes with the surfactantconcentration (see Fig.1)This clearly shows that coil and globule form coexistin the surfactant solution at a concentration intervalin which the cooperative continuous transition isobserved in the macroscopic ensemble of DNAchains. It is the first time, to our knowledge, that thecoil-globule coexistence is observed in bulk, in adirect way. The overall phenomenology observed forCTAB and DDAO surfactants is quite similar,although, in the latter one, the pH-induced degree ofprotonation is small. This finding clearly indicates theimportant role of the hydrophobic interactions in theformation of DNA-surfactant complex.References[1] S.M. Mel'nikov, V.G. Sergeyev, K. Yoshikava, J.Am. Chem. Soc., 117, 2401, (1995).[2] Y.S. Mel'nikova, B. Lindman, Langmuir , 16,5871, (2000).[3] S.Marchetti, G. Onori, C. Cametti, Journal ofPhysical Chemistry B., 109, 3676, (2005).[4] A. Bonincontro. S. Marchetti, G. Onori, A. Rosati,Chem. Phys., 312, 55, (2005).Fig. 1: Average hydrodynamic diameter 2R H of DNA-CTAB complexes as a function of the surfactant toDNA-phosphate molar charge ratio X. The insetshows the size distribution at two different values ofX, before and close to the neutralization condition,X=0.55, where there is a bimodal distribution andX=1.22, where only a monomodal distributionappears.AuthorsG. Onori (a), S. Marchetti (a), C. Cametti (b)(a) Dipartimento di Fisica, Università di Perugia andCEMIN and INFM-CRS SOFT, Unità di Roma 1.(b) Dipartimento di Fisica, Università di Roma « LaSapienza », Piazzale A. Moro 5, I-00185- Roma(Italy) and INFM- CRS SOFT, Unità di RomaSOFT Scientific Report 2004-0694

Multi-Scale Coarse-Graining of Diblock Copolymer Self-Assembly: From Monomers to Ordered MicellesFig. 1: (a) Single configurationof 5000 dumbbells atdensity beyond the cmc.Red and blue indicate theideal and self avoiding strandsof the copolymersrespectively. (b) Position ofcentre of mass of the micellesfor the same system. (c)Ordered phase at slightlyhigher density.Block copolymers in solution show a remarkable tendencyto self-assemble into a bewildering range ofdisordered (liquid-like) and ordered structures, dependingon the macromolecular composition, therelative sizes of the blocks, solvent selectivity, polymerconcentration and temperature [1]. A frequent,partial scenario sees the copolymers aggregate intopolydisperse spherical micelles at low polymer concentration;upon lowering the temperature or increasingthe concentration, the micelles undergo adisorder-order transition onto a cubic lattice. Atheoretical understanding of copolymer phase behaviourgenerally relies on self-consistent field theorysimilar to that applied earlier to copolymer melts[2]. A more molecular approach is ob-viously verydifficult, in view of the wide range of length scalesinvolved, from themonomer level to themesoscopic scales characterisingordered micellarstructures.We have recently implementeda two-stagecoarse graining strategyto investigate the micellizationand disorder-ordertransition of a simplemicroscopic model ofdiblock copolymers in aselective solvent [3]. Westart considering AB copolymersmade up oftwo blocks of equalnumbers M A=M B=M ofmonomers on a cubiclattice. The solvent selectivitywith respect toA and B monomers isrepresented by modellingthe A blocks as idealchains (I) and the Bblocks as self and mutuallyavoiding walks (S).Moreover A and B blocksof the same or differentcopolymers are assumedto be mutually avoiding(S). The model is clearlyathermal and the polymerdensity is the onlythermodynamic variable.With typical polymersizes M~10 3 , and expectedmicelle aggregationnumbers n~10 2 ,very large system sizeswould be needed to generatethe tens of micellesrequired to studytheir ordered and disorderedstructures. At thefirst stage of our coarsegrainingprocedure, ABcopo-lymers are mappedonto “ultrasoft” dumbbells with effective interactionsbetween the centres of mass (CM) of A and B blockson different copolymers, and an intramolecular“tethering” potential between the CM's of the twoblocks of the same copolymer. These effective interactions,of purely entropic origin, are obtained byinverting the A-A, A-B, and B-B CM-CM intermolecularand intramolecular pair distri-bution functions inthe low density limit [4]. The obtained effective potentialsare roughly gaussian in shape with an amplitudeof a few k BT, and a range of the order of thegyration radius of the copolymer. Earlier experiencewith homopolymers shows that assuming the transferabilityof zero density potentials to finite density isnot an unreasonable approximation well into thesemi-dilute regime. By Monte Carlo simulation of theeffective dumbbell model, we have observed that micellizationsets in beyond a critical micellar concentrationwith the ideal A-blocks forming the densecore and the B-blocks forming the corona. With aperiodic sample of 5000 AB copolymers beyond thecmc (fig. 1) we observe about 50 moderatelypolydisperse micelles. A further increase of concentrationproduces a disordered-ordered transition,from a liquid-like structure into a micellar cubicphase with defects, in qualitative agreement withexperimental observation. At the second level ofcoarse graining we consider the structure of thesystem of micelles regarded as spherical particles.Within the HNC theoretical framework [5], an effectivemicelle-micelle pair potential can be extractedfrom the pair distribution function between micellecentres of mass. The resulting effective pair potentialexhibits a relatively soft repulsion that culminates ata value of roughly 12 K BT at the origin, followed by ashallow attractive well. This kind of potentials cangive rise to a freezing transition at sufficiently highdensities as we have indeed observed. Extension ofthe above coarse-graining strategy to more generalmodels is being pursed in order to reproduce the richexperimental phase diagram of dilute diblock copolymerssolutions in selective solvent.References[1] T.Lodge et al, Faraday Discussions 128, 1 (2005)[2] L. Leibler, Macromolecules 13, 1602 (1980);G.H. Frederickson and E. Helfand, J. Chem. Phys.87, 697 (1987); M.W. Matsen and M. Schick, Phys.Rev. Lett. 72, 2660 (1994).[3] C. Pierleoni, C.I. Addison, J.-P. Hansen and V.Krakoviack, submitted to Phys. Rev. Letts., January2006; cond-mat/0601417.[4] C.I. Addison, J.P. Hansen, V. Krakoviack and A.A.Louis, Molec. Phys. 103, 3045 (2005).[5] J.-P. Hansen and I.R. McDonald, “The Theory ofSimple Liquids”.AuthorsCarlo Pierleoni (a) , Chris Addison (b) , Jean-Pierre Hansen(b) and Vincent Krakoviack (c)(a) INFM CRS-SOFT, and Department of Physics, U. ofL'Aquila, I-67010 L'Aquila, Italy,(b) Dept. ofChemistry, University of Cambridge, Cambridge CB21EW, United Kingdom(c) Laboratoire de Chimie, Ecole Normale Supérieurede Lyon, 69364 Lyon Cedex 07, France.95SOFT Scientific Report 2004-06

Scientific Report – Self Assembly, Clustering, Structural arrestBernal Spiral Clusters in Colloid-Polymer MixturesHard spheres colloidal particles in suspension withsmall non-adsorbing polymers interact via aneffective attractive depletion potential, controlled inrange by the polymer-to-colloid size ratio and inmagnitude by the polymer concentration. Often,colloidal particles are also slightly charged, so that along-ranged repulsion of screened electrostatic typecomplements the short-range attraction. In theabsence of charge, at low densities, colloidalparticles undergo gas-liquid (colloid poor-colloid rich)phase separation, before the dynamics becomessufficiently slow. However, when electrostaticrepulsion becomes non-negligible, the competitionbetween the short-range attraction and the longrangerepulsion produces what may be viewed as amicrophase separation into colloidal aggregates offinite size, also called `equilibrium cluster phase'.This corresponds to a fluid made on average ofclusters, which can break and reform in equilibrium,but whose properties as a structurally distinct stateare clearly visible, as for example in the staticstructure factor which displays a characteristic peakat a finite wave-vector, much smaller than thetypical nearest-neighbour wave-vector. Modeling theeffective colloidal pair interactions as the sum of ageneralized Lenard-Jones potential with exponent♋ mimicking the hard-core repulsion and theshort-range attraction, and of a Yukawa term ofamplitude A and screening length ξ, ground statecalculations[1] have shown that cluster formation isfavoured with respect to bulk liquid separation, uponvarying the potential parameters, and that,moreover, the shape of such clusters can be tunedfrom spherical to linear, when the repulsion changesfrom long-ranged to relatively short-ranged, i.e.comparable to the particle radius. In the latter case,confocal microscopy experiments [2] have providedevidence of the existence of such clusters, organisedin the structure of the so-called Bernal spiral, i.e. athree-stranded spiral of face-sharing tetrahedra (seeFig.1a). At high enough density clusters are found tobranch and percolate, forming a disordered arrestednetwork, i.e. a gel.Focusing on the potential parameters related to theexperimental results [2], extensive molecular andbrownian dynamics simulations were carried out [3]in order to check whether such elongated clustersexist and if a simple pair potential of the kinddescribed above is sufficient to reproduce theexperimental results. We find that, indeed, at lowtemperature the system structure is of the Bernalspirall type. At low packing fractions 0.1, since the residual interactionsbetween the spirals are small, they can branchthrough some defects allowed by the finiteFig. 1. Bernal SpiralFig. 2a. High TFig. 2c. Low TFig. 2b.Intermediate Ttemperature and thus forming a solid percolatingstate with non-ergodic features. Interestingly, in thislatter case, by decreasing temperature from high tolow, a reentrant percolation is observed. This isshown in Fig.2. At first, temperature is too high, andcluster just percolate transiently in a totally randomway. As temperature is lowered, a competitionbetween entropic and energetic effects takes place,so that the clusters become smaller in size, they donot percolate any more and they start to displayfeatures of the Bernal spiral. Further lowering of thetemperature produces a stable network ofpercolating spirals, again of random nature. Thus atransition from monomers to spiral clusters takesplace as subunits of the system.References[1] S.Mossa, F.Sciortino, P.Tartaglia, and E.Zaccarelli, Langmuir 20, 10756 (2004).[2] A. I. Campbell, V. J. Anderson, J. van Duijneveldtand P. Bartlett, Phys. Rev. Lett. 94, 208301 (2005).[3] F. Sciortino, P. Tartaglia, and E. Zaccarelli,Journal of Physical Chemistry B 109, 21942 (2005).AuthorsE. Zaccarelli(a,b), F. Sciortino(a), P.Tartaglia(c)(a) Dipartimento di Fisica and CNR-INFM-SOFT,Università di Roma La Sapienza, P.le A. Moro 2, I-00185 Roma, Italy; (b) ISC-CNR, Via dei Taurini 19,I-00185, Roma, Italy; (c) Dipartimento di Fisica andCNR-INFM-SMC, Università di Roma La Sapienza,P.le A. Moro 2, I-00185 Roma, ItalySOFT Scientific Report 2004-0696

Molecular Clustering by High Resolution NMRAmong all self-aggregation processes, the selfaggregationof lipid molecules to form bilayermembranes is a process fundamental to theorganization of life. Thanks to their spontaneoustendency to aggregate, some lipid moleculesconstitute local phases of highly concentratedorganic compounds, embedded in the membrane andtherefore could enhance concentration dependentchemical interactions.temperature dependence has given us usefulinformation on clusters formation, making itsdependence on temperature and gangliosideconcentration more clear.References[1] D’Emiliano D., Casieri C., Paci M. and De Luca F.2006. Detection of Ganglioside Clustering in DOPCBilayers by 1H-NMR Spectroscopy. PhysicaA (2006),doi:10.1016/j.physa.2006.07.021.AuthorsD. D’Emiliano (a,b), C. Casieri (a,c) and F. De Luca(a,b).(a) CRS SOFT-INFM-CNR, Roma, Italy(b) Dip. di Fisica, Univ. di Roma La Sapienza, Roma,I(c) Dip. di Fisica, Università di L’Aquila, L’Aquila, IFig. 1: The appearance of the resonance shift onCH=CH 1H-DOPC line in function of GM1concentration.1H-NMR spectroscopy has been used [1] toinvestigate the formation of ganglioside GM1 clustersin DOPC liposome bilayer. The 1H-DOPC NMR spectrashow that the presence of GM1 modifies someresonance lines (fig. 1). These modifications areimputable to the interaction of DOPC with GM1.Above a certain GM1 concentration the trend of suchdistortions suggests the formation of GM1aggregates. Our work provides a new and simpleNMR proof of the GM1 clustering in DOPC liposomesand therefore on model cell membranes; it allows toestimate the mean size of GM1 aggregates and theGM1 concentration at which clustering starts. Inaddition, NMR-PFG self-diffusion coefficientmeasurements have enable us to confirm and extendthe chemical shift results. Thanks to our approachthe influence of cluster formation on the generalorganization of the DOPC bilayer has been shown. Inparticular its local disordering effect on DOPC-DOPCinteractions has been proven. More over, cluster radiiTwo binary aqueous mixtures which contain thesmall amphiphilic molecules TMAO (trimethylamine-N-oxide) and TBA (tert-butyl alcohol) have beeninvestigated by molecular dynamics simulations andNMR chemical shift and self-diffusion measurements.TMAO is an osmolyte, while TBA is a monohydratealcohol. Both possess bulky hydrophobic groups andpolar heads, namely, NO in TMAO and OH in TBA.The hydrophilic/hydrophobic content of theseisosteric molecules strongly modulates the structureand dynamics of the hydration shell, which isthought to be responsible for the effects observed onproteins and phospholipids. Simulation results,especially on hydrogen-bond networking, spatialcorrelations, and self-diffusivity, are consistent withNMR data and agree well with previous numericalstudies on similar solutions. The methods employedallow the elucidation of the microscopic features ofthe solutions. For TBA solutions, the hydration shellis found to have a low density and a large spatialspread, and thus, above the molar fractionof 0.03,reduction of hydrophobic hydration drives selfaggregationof the solute. This effect does not takeplace in TMAO solutions, where the hydration shell ismore compact and stable, maintaining its structureover a wider range of solute concentrations.References[1] Sinibaldi R., Casieri C., Melchionna S., Onori G.,Segre A.L., Viel S., Mannina L. and De Luca F., J.Phys. Chem. B, 110 (2006) 8885-8892.Authors:R. Sinibaldi (b), C. Casieri (a,c) and F. De Luca (a,b).(a) CRS SOFT-INFM-CNR, Roma, Italy(b) Dip. di Fisica, Univ. di Roma La Sapienza, Roma,I(c) Dip. di Fisica, Università di L’Aquila, L’Aquila, I97SOFT Scientific Report 2004-06

Scientific Report – Self Assembly, Clustering, Structural arrestNon-invasive 1 H-NMR in porous materials of artistic interestNuclear Magnetic Resonance of 1 H-nuclei of waterconfined in porous media has become anirreplaceable tool for quantitative characterization ofthe structure of porous media. Proton relaxationexperiments allows evaluation of the equilibriumnuclear magnetization and extraction of distributionsfunctions of the relaxation times (T 1 and T 2), whichin fully water saturated condition may be interpretedin terms of porosity and “pore-size” distributions,respectively. The ability to use water molecules toexplore the pore space makes NMR methodsespecially appropriate for studying materials ofCultural Heritage interest. In fact, porous materials(i.e. concrete, mortar, stone, wood) can absorb orrelease water in response to thermo-hygrometricenvironmental modifications and their properties aregreatly affected by moisture content. Moreover,trapped water can dissolve the components ofporous media, altering their porosity andtransporting air pollutants inside the pore space,causing corrosion and micro-fractures. Therefore, theknowledge of capillary properties and porosity ofartworks materials is essential for the evaluation ofthe conservation state and suitable non-destructivediagnostic techniques are required. Recently, all theNMR capability of studying porous systems hasbecome available for Cultural Heritage applications,thanks to the development of portable surfaceprobes such as the mq-ProFiler. Various are thetopics concerning the field of science for CulturalHeritage explored by single-sided NMR, some ofwhich are reported in the following.Determination of moisture fraction in wood. Themobile NMR probe has been used as a non-invasivetool for water content analysis on wood samples. Theporosity index, expressed as the fraction of thesensitivity volume of the probe occupied by waterhas been proposed as an alternative to moisturecontent index, namely the amount of water masswith respect to the mass of dried sample. In principlethe method can be applied to any kind of porousmedia that has no detectable proton signal from therigid matrix as, for instance, in building materials. Inwood, where proton signal can be detected also fromcellulose or other macromolecular components, someconsiderations and artifices have been proposed foreliminating this contribution. This method hasallowed performing moisture volume fraction analysison wood samples characterized by different woodspecies, cutting and moisture content. The NMR datahave succesfully been compared with those obtainedby the gravimetric method.References[1] Casieri C., Senni L., Romagnoli M., SantamariaU., De Luca F., J. M. R., 171 (2004) 363-372.[2] Casieri C., Senni L., Romagnoli M., SantamariaU., De Luca F., in 8th Int. Conf. on “Non-destructiveTesting and Microanalysis for the Conservation of theCultural and Environmental Heritage”, 15-19 May2005, Lecce. ISBN 88-89758-00-7.AuthorsL. Senni (a,b), C. Casieri (a,c) and F. De Luca (a,b).NMR evaluation of hydrophobic treatments forstone conservation. The aim of this experimentwas to check the ability of NMR methods toquantitatively follow the absorption phenomenonunder different wettability conditions of the internalpore surfaces in “Lecce Stone”. A hydrophobicpolymer (PB72) has been applied through one face ofeach sample and relaxation data have been takenover the course of time without interrupting theabsorption process, simply by keeping the portabledevice on the surface opposite to the absorption. Themain experimental evidence was that for a sampletreated with a high amount of PB72 (478 mg in 3%(w/w) chloroform solution) when the absorption faceis the untreated one (Fig. 1a) initially the capillaryrise of water is reduced by the hydrophobic productand limited to smaller pores or to larger ones onlypartially filled with water. However, after the firsthours of absorption, the water molecules find a waythrough the polymeric barrier and invade all the porespace available at normal pressure conditions.Instead, when the absorption face is the treated one(Fig 1b), the signal density distributions are limitedto only the region of smaller T 2 for every absorptiontime, indicating that the larger pores throughoutmuch of the sample have become somewhat waterrepellent.The results have been confirmed byMagnetic Resonance Imaging analysis, showing thatthe single-sided technique is a powerful tool for insitu evaluation of water-repellent treatments usedfor consolidation and/or protection of stone artifacts.(a)(b)Fig. 1: Water uptake kinetics in 2D visualization forthe time evolution of the T 2 distribution through theuntreated face (a) and measurement from thetreated one (b) for the treated sample.References[1] Bortolotti V., Camaiti M., Casieri C., De Luca F.,Fantazzini P., Terenzi C., JMR, 181 (2006) 287-295.[2] Camaiti M., Casieri C., De Luca F., Fantazzini P.,Terenzi C., Studies in Conservation, (2007).[3] Casieri C., De Luca F., Fantazzini P., J. Appl.Phys. 97(4) 043901 (2005) 1-10.Authors:C. Terenzi (a,b), C. Casieri (a,c) and F. De Luca(a,b).(a) CRS SOFT-INFM-CNR, Roma, Italy(b) Dip. di Fisica, Univ. di Roma La Sapienza, Roma,I(c) Dip. di Fisica, Università di L’Aquila, L’Aquila, ISOFT Scientific Report 2004-0698

Ion Density Fluctuations in Liquid GalliumThe study of ion density fluctuations in the THzrange in metals is a basic branch useful to derivegeneral information on the fluid dynamics. Inaddition, these studies allow to use the ions inmetals as weak probes of the electron fluid responseat low frequency. Indeed, the effective ion-ionpotential is mediated by the electron fluid throughthe dielectric response in a frequency region which isquite small as compared to the Fermi energy, so thatthe electron response can be safely considered asstatic.Despite the long standing research devoted to theanalysis of the electron gas properties, this is still aforefront problem of many body physics.Neutron and photon scattering are the most powerfultools for the investigation of the ion dynamics incondensed systems from crystals to gases.We present here an investigation of the ion dynamicsin liquid Gallium by means of neutron[1] and x-rayscattering[2], as well as, molecular dynamicssimulation[1]. Although liquid alkali metals are theprototype for the study of the electron response,polyvalent metals are also very interesting since theyprovide information on the electron gas at higherdensity than alkali metals, other than additionalinformation on the role of the ion core repulsivepotential. The experimental results of Refs. 1 and 2are summarized in Fig. 1, where the experimentalresults from neutron and x-ray scattering arepresented in comparison to a large scale moleculardynamics simulation. The very good agreementbetween simulation and experiments gives a strongsupport for the ion-ion potential employed in thecomputer experiment. This potential is directlydeduced from the electron gas properties and it isable to reproduce, without adjustable parameters,the experimental results at two quite differenttemperatures. The form we employed is directlydictated from the electron gas response plus arepulsive contribution equal to that used in thestandard Lennard-Jones potential. Therefore theeffective two body potential includes many bodyeffects both the ion liquid and electron liquid throughthe density of the system. In the present simulationthe potential is given by:related to the electron density. The coefficient VRand VF are deduced by comparing the simulated andexperimental structure factors at room temperature.The pair potential proves its effectiveness by beingable to reproduce the static structure factor at hightemperature (970 K) without adjustable parameters.In addition the simulation is quite effective inproviding a good agreement with the experimentalresults for the dynamic structure factor as measuredat room temperature and 970 K by neutronscattering and at room temperature by x-rayscattering.References[1] L. E. Bove, F. Formisano, F. Sacchetti, C. Petrillo,A. Ivanov, B. Dorner, and F. Barocchi, Phys. Rev.B71, 014207 (2005).[2] T. Scopigno, A. Filipponi, M. Krisch, G. Monaco,G. Ruocco, and F. Sette, Phys. Rev. Lett. 89, 255506(2002).AuthorsL. E. Bove,1 F. Formisano, C. Petrillo, F. SacchettiDipartimento di Fisica, Università di Perugia, CRS-SOFT Unità di Perugia and Centro per i MaterialiInnovativi e Nanostrutturati (CEMIN), Via A. Pascoli,I-06123 Perugia, Italy.99SOFT Scientific Report 2004-06

Scientific Report – Elastic and inelastic scattering of neutrons and X-raysFemtosecond dynamics in Ferromagnetic MetalsIn electronic Resonant Raman Scattering (RRS) thesample is resonantly excited at a core threshold anda photon is emitted bringing the sample to the finalstate. This process sets a characteristic time scaleconnected with the lifetime of the intermediate statecore hole. If there is an evolution of the systemalong this time scale the effect is seen in the spectralfunction [1]. For this reason this approach to thestudy of fast processes is called core hole clock. Thepresent work is to our knowledge the firstimplementation of the core hole clock in the study ofmagnetism. This is done in ferromagnetic metals(Fe-Co-Ni) in the scattering channel 2p 6 3d n + hν in →2p 5 3d n+1 → 2p 6 3d n+1 3s 1 + hν out, where n is the 3doccupation number in the ground state and hν in andhν out are the incident and outgoing photon energies(in this case hν out is about 100 eV lower than hν in).We use the so called Integrated RRS (IRRS) [2]where one measures, as a function of hν in, theintegral of the scattered intensity in the scatteringchannel. The geometry is shown in the upper panelof Figure 1. The IRRS spectra show an effect notpresent in ferromagnetic insulators. A magneticcircular dichroism (MCD) is seen in IRRS spectra alsoin those regions between L 3 and L 2 and above L 2where the usual XMCD gives no signal (see the lowerpanels on Co in the figure where the red areas showthis effect on the IRRS dichroism given in green).This is due to the spin dependent screening takingplace in the intermediate state [3] so that the corehole becomes polarised. In order to take place, thisprocess requires a non zero magnetic moment of thesystem. In the fully relaxed theoretical model of ref.[3] the dichroism (more exactly the flipping ratio)depends on the local magnetic moment of theexcited site once the core hole is fully screened. Thecrucial experimental information given here is thetrend of this dichroism (flipping ratio) along thesequence Fe-Co-Ni and in particular the fact that Ni-100.20770 790 810 770 790 810Fig.1.L 3 L 13LL 22XMCDCo metalIRRS-MCDA0Fig. 2.metal shows clearly this effect. This is importantsince in a fully relaxed situation we should see noeffects because a well screened core hole in Ni givesessentially a 3d 10 configuration with almost zeromagnetic moment. Thus along the characteristic timescale of the scattering (typically 1-2 femtoseconds)Ni has not the time to develop the spin dependentscreening of the Fermi gas.More can be seen from Figure 2 where thehistograms give the magnetic moments of therelaxed and unrelaxed sites [3] in comparison withthe flipping ratio of the IRRS-MCD given by the reddots. The data are normalised to one in the case ofFe where a relaxed model accounts for the effect asseen in Auger spectroscopy [3]. The trend showsthat Co is somewhere in between the fully screenedand unscreened situation whereas Ni is basicallyunrelaxed. Thus Ni is much slower in building up thescreening and we attribute this behaviour to thenarrow band nature of the Ni-3d holes while the Feand Co case are certainly much more itinerant. Inthis sense we see a link between the correlationproperties and the magnetic dynamics along shorttime scales. In conclusion the use of the core holeclock in soft x-ray resonant scattering points out asubstantially slower dynamics in Ni in comparisonwith Fe and Co.References[1] P.A. Brühwiler, O. Karis, and N. Mårtensson,Rev. Mod. Phys. 74, 703-740 (2002) and referencesquoted therein.[2] L. Braicovich et al. , Phys. Rev. Lett. 90, 117401(2003).[3] A. Chassé et al. , Phys. Rev B 68, 214402(2003) and references quoted therein.AuthorsL. Braicovich (a), G. Ghiringhelli (a), A. Tagliaferri(a), G. van der Laan (b), E. Annese (c), and N. B.Brookes (d)(a) INFM-CNR and Dip. di Fisica, Politecnico diMilano, Italy; (b) Magnetic Spectroscopy, DaresburyLaboratory, UK; (c) TASC, Trieste, Italy; (d)European Synchrotron Radiation Facility, Grenoble,France.SOFT Scientific Report 2004-06100

Soft Resonant X-ray Scattering (RIXS) from solids:Results on InstrumentationA X Em d va nc ed -Ra y issio n Sp ec tro sc op ySAXES& Swiss Lig ht So urc ePolitecnico di Milanoallowing to scan the scattering cross section at allangles. The second instrument is less versatile interms of angular scan but is much more effective inthe selection of the energy window because it isbased on a multilayer system. In this case it is alsopossible to carry out the polarization analysis of thescattered radiation.It is in the scientific tradition of the AXES group todevelop new instrumentation at the forefront of theinternational standard. This implies a continuousupgrading of the existing instruments and the designand development of new machines. In thisconnection the main achievements are the following.1. Equipment for RIXS measurements at the ESRF(ID08 beamline)This is the instrument used at the ESRF to takespectra with resolution both in the incident and inthe scattered photon beam. The instrument entirelydeveloped at the Politecnico di Milano and fullysupported by INFM/CNR consists of amonochromator used to prepare the incident beam(this instrument is called Polifemo) and in aspectrograph used to measure the scattered photonenergy past the sample (this instrument is calledAXES). The first spectra from AXES came out in 1994with white beam excitation and Polifemo wasinstalled in 1997. Due to continuous upgrading onlythe mechanical setup remains essentially the same.A part of the optics has been changed and thedetector (a CCD ) is completely new. Thanks to theseimprovements the system has top levelperformances at the international level among theinstruments operated routinely in the range from450 eV to about 1300 eV. The typical resolvingpower around 600 eV is 2000 (note that this is thecombined resolving power including both Polifemoand AXES).3. Equipment for RIXS measurements at the SwissLight Source (ADRESS beamline)This instrument is property of the Paul ScherrerInsitut (PSI, Villigen, Switzerland) and has beendesigned and built at the Politecnico di Milano. Itexploits the expertise accumulate by our group in the10 years of the AXES project and is conceived toreach even better performances. For this reason theinstrument is called SAXES (Super-AXES). It isdesigned to have a resolving power around 8000-10000 and it will be mounted on a rotating opticalbench in order to do measurements as a function ofthe transferred momentum. The better energyresolution is obtained at the price of a lowerefficiency in SAXES than in AXES: the twospectrometers are complementary and they will beboth kept operational in the future. SAXES shouldbecome operational at the ADRESS beam line of theSwiss Light Source at the beginning of 2007. Thefirst tests on energy resolution made withconventional x-ray sources in Milano have shownthat the target performances have been reached.SAMPLEAREA INCLUDED INTHE SPECTROMETERACCEPTANCEILLUMINATEDSURFACEINCIDENTBEAM2D POSITIONSENSITIVEDETECTOREMITTEDPHOTONSSPECTROMETERENTRANCE SLIT SPECTROMETERGRATING2. Equipments for Integrated Raman (IRRS)measurements at the ESRF (ID08 beamline)We have developed two instruments to exploit thisnew experimental approach. The first instrumentselects the scattering channel with absorption filtersinstalled on a goniometer in ultra high vacuumPartecipantsL.Braicovich, C.Dallera, G.Ghringhelli, A.Tagliaferri,A. Piazzalunga, F. Fracassi, INFM-CNR and Dip. diFisica, Politecnico di Milano, Italy.101SOFT Scientific Report 2004-06

Scientific Report – Elastic and inelastic scattering of neutrons and X-raysPicosecond-Timescale Fluctuations of Proteins in GlassyMatrices: The Role of viscosityProteins perform most of the functions of livingthings. They are real nano-engines, whosefunctioning deserves to be studied in action.Actually, despite its importance, the precise natureof the internal motions of proteins remains amistery. In particular fast relaxations in thepicosecond-timescale play a key role for biologicalactivity. When proteins are embedded in glassymatrices both the onset and the amplitude of thesefluctuations appear to be driven by the environmentjust around the protein surface [1]. Here we report astudy performed via elastic neutron scatteringexperiments at the backscattering spectrometerIN13 [2]. In particular we investigated lysozyme, asimple model enzyme, in the hydrated powder stateand when it is plunged in different kind of glassymatrices, in the temperature range 20 ÷ 320 K. Thecalculated protein mean square displacements (MSD) follow a purely vibrational behaviour at lowtemperature.MSD show a temperature critical behaviour that istightly linked with that of η, with crucial changes justin proximity of the glass transition. Indeed, theinternal dynamics of proteins is strongly determinedby the ability of the surface protein side-chains tomove. If we describe the picosecond timescalemotions of a particle in terms of Brownian diffusion,then the Stokes-Einstein law leads to an inverserelationship between the relevant MSD and bulkviscosity ~η -1 . Actually, from our results itfollows that ~(logη) -1 . This weaker dependencecould be due to the fact that it is the microviscositysensed by the particle, possibly different from η,which is related to the corresponding dynamics. Inaddition, the evidence that both solvent and proteinMSD are related to η by the same functionaldependence indicates that the protein local dynamicsis closely coupled with that of the host. Thus ourfindings indicate that it is just the molecular networkimmediately around the protein surface to drive thefast fluctuations in proteins.log(η in Poise)1086420lysozyme+glycerol0h-20.42h0.83h-40 2 4 6 8 101/6 2w(Å -2 )Fig. 1. Logarithm of solvent bulk viscosity vs. theinverse of the protein double-well (relaxational)contribution to total mean square displacements (h =grams of water/grams of lysozyme).At around 100 K a gradual departure from thisvibrational behaviour takes place. This marks theonset of jumps from the ground to the excited statein a double-well model with corresponding MSD of 2w. In Fig. 1 we represent the logarithm of thebulk viscosity η of some glycerol-water mixtures vs.the inverse of 6 2w of lysozyme in thecorresponding glycerol-water matrices. Quitesurprisingly we observe that a linear relationshipexists in the whole investigated temperature range.We verified that such a law is obeyed in all thesystems we studied, as Fig. 2 shows. It should beremarked that the linear relationship between logηvs. 1/6 2w is satisfied also in some glass formers[3]. Anyway, in these materials it is the bulkviscosity and the fast dynamics of the same systemthat are correlated. What’s the meaning of therelationship we found in a complicated system suchas a protein in glassy environments? The existenceof a linear dependence tells us that protein relaxationlog(η in Poise)1412108642012 108641/6 2w(Å -2 )200.20.00.40.60.81.0 hFig. 2. The law logη ~ 1/6 2w is verified for allthe measured samples. Lysozyme at 0.3h (purple)and 0.4h (violet); lysozyme in glycerol at 0h (blue),0.2h (gray), 0.42h (red) and 0.83h (black);lysozyme in glucose at 0h (pink), 0.15h (orange),0.41h (dark green), 0.59h (cyan) and 0.71h (green).References[1] A. Paciaroni, S. Cinelli, G. Onori, Biophys. J. 83,1157 (2002).[2] E. Cornicchi, G. Onori and A. Paciaroni, Phys.Rev. Lett. 95, 158104 (2005).[3] U. Buchenau, and R. Zorn, Europhys. Lett. 18,523 (1992); J. C. Dyre and N. Boye Olsen, Phys.Rev. E 69, 042501 (2004) and references therein.AuthorsE. Cornicchi, G. Onori and A. PaciaroniDipartimento di Fisica, Università di Perugia, CRS-SOFT Unità di Perugia and Centro per i MaterialiInnovativi e Nanostrutturati (CEMIN), Via A. Pascoli,I-06123 Perugia, Italy.SOFT Scientific Report 2004-06102

Neutron inelastic scattering on liquid CD 4 : a fruitful probe ofthe dynamics in simple molecular liquidsThe limited experimental work devoted in theseyears to the determination of the dynamic propertiesof simple molecular liquids has nonetheless producedextremely interesting results concerning thedispersion law of collective excitations and the quitedifferent role of damping with changing the system[1]. Moreover, comparison with monatomic fluids canfurther enrich the accessible information on thegeneral dynamic behavior of these liquids. Ourrecent neutron investigation on liquiddeuteromethane (CD 4) allowed, in particular, forstimulating steps forward in the individuation of thebasic phenomena ruling the actual extension of thepropagation Q-range of collective excitations indisparate mono- and polyatomic fluids [2].Remarkable differences between our results for CD 4and those for other molecular liquids as ammonia,carbon tetrachloride, and sulphur dioxide [1] werefound, pointing in particular at the strikingly differentvalues found for Q t*, i.e. the reduced wavevectortransfer threshold value at which modes wereobserved to cease propagation in these liquids(Q*=Q l, with l the mean free path). For instance,Q t* ~ 2 for the liquids of Ref. [1]. Differently, in CD 4Q t* ~ 6, as it can be deduced (with a mean free pathl ~ 0.4 nm for the CD 4 sample under consideration)from comparison of the Q-dependences of excitationfrequency and width (HWHM), both shown in Fig. 1.The results for CD 4, fairly supported also by asatisfactory agreement with MD simulations based onrealistic site-site interactions [2], show instead moremarked similarities with monatomic liquids as Ar andNe. Such resemblances are suggested both by thecomparisons wih Ar data shown in Fig. 1, and by thetypical Q t* values (of the order of 6) of liquid Ar andNe [3].This overall picture led us to individuate an empiricalrelation, approximately valid for all the liquidsmentioned here, between the Q t* values at whichmodes overdamping is observed to occur, and thebasic interaction and transport properties of thefluid. Such a relation is Q t* Γ* ≈ const., with Γ* thereduced sound damping coefficient defined byΓ* = (m/ε) 1/2 Γ / σ. Here ε and σ can be taken as theeffective Lennard-Jones parameters for the variousfluids, and Γ is defined, as usual, in terms of thermaldiffusivity, bulk and shear viscosities, and specificheats ratio [2,3]. For all the liquids we could findacceptable experimental dynamical data, we findQ t* Γ* ≈ 19 within 11%. Even smaller fluctuationsare obtained by omitting the bulk viscositycontribution, unavoidably deriving from approximateestimates. In such a case, thus referring only toshear viscosity experimental data, we findQ t* Γ shear* ≈ 15 within 7%.Thus, apparently contrasting dynamic behaviors turnall out to follow, as far as the propagation range ofexcitations is concerned, the above approximateempirical relation, which provides a first evidence ofthe important interplay between attractive forces anddamping mechanisms in determining the transitionto the non-propagating regime in a liquid. Such asemi-quantitative relation, if confirmed by more thanthe few test-cases available, can indeed provide areasonable tool to predict the range whereexcitations in a liquid are expected to propagate.Nonetheless, a unified picture of the dynamics ofmono- and polyatomic fluids is still far from hand,especially when the Q-dependence of the modeswidth is analysed in different systems.References[1] F. J. Bermejo et al., J. Chem. Phys. 95, 5387(1991); M. García-Hernández et al., J. Chem. Phys.96, 8477 (1992) ; F. Sette et al., Phys. Rev. Lett.84, 4136 (2000).[2] E. Guarini et al., Europhys. Lett. 72, 969 (2005).[3] A. A. van Well and L. A. de Graaf, Phys. Rev. A32, 2396 (1985).[4] U. Bafile et al., Phys. Rev. Lett. 65, 2394 (1990).Fig. 1 Q-dependence of the frequency (top) andHWHM (bottom) of collective modes in liquid CD 4:experimental (circles) and MD (stars) results. Fullsquares are Argon data read off from Fig. 12(a) ofref. [3]. In both frames, the dotted and dash-dottedcurves are the full hydrodynamic solutions [4]calculated, respectively, for CD 4 and Ar.Authors:E. Guarini (a), F. Barocchi (a), G. Venturi (a), U.Bafile (b), F. Formisano (c), M. Sampoli (d).(a) CNR-INFM, Dipartimento di Fisica Firenze, CRS-Soft; (b) CNR-ISC Firenze; (c) CNR-INFM, OGGGrenoble, CRS Soft; (d) Dipartimento di EnergeticaFirenze, CRS-Soft103SOFT Scientific Report 2004-06

Scientific Report – Elastic and inelastic scattering of neutrons and X-raysThe Dynamics of Dilute H 2 Enabling New Calibration Methodsin Neutron SpectroscopyThe never fading scientific interest in the simplestand most fascinating molecular system, fluid H 2, haslately been revived by the possibility of convertingthe knowledge of its dynamic response to slow andthermal neutrons into a powerful technique for datanormalization in inelastic neutron scatteringexperiments. This possibility was, until very recently,IH2 [arb. units]α0 ≈ 30’a)6 x 10-3 E f = 50 meV5θ = 2°4321E [meV]0-20 -15 -10 -5 0 5 10b)c)α1 = 40’MonochromatorCu(111)Monitorθ MSamplej-th cell:θ j , ∆Ω j , ε jSlitsα2 = α1θFilterα3 = 60’3 He DetectorAnalyzerCu(111)/PG(002)i-th cell:θ i , ∆Ω i , ε iFig. 1: a) Experimental setup; b) Neutron spectrumof dilute H 2 (blue dots) compared with semiclassical(green curve) and quantum (red curve) predictions;c) The big BRISP detector inside its long vacuumchamberat the ILL, ideally subdivided into a 2Darray of square detection cells (see text).θ Ahindered by the absence of an experimentalverification of available theoretical predictions for theH 2 roto-translational neutron spectra in the dilute,room temperature, phase.A successful attempt to overcome this lack ofinformation, carefully testing the dynamical modelsagainst first neutron data for low-density H 2, wasrecently performed [1] by means of three-axisspectrometry (IN3 instrument at ILL), using theinstrumental configuration shown in Fig. 1 a). Thedynamic response of dilute hydrogen was measuredat two fixed final neutron energies, namely E f = 14.7and 50 meV, and rather low scattering angles, i.e. inthe most demanding cases for theoreticalmodelization and, at the same time, in the mostuseful conditions for the setting up of a valuable andalternative method to the well-known vanadiumcalibration technique in neutron spectroscopy, whichcan lose accuracy at low momentum transfers. Adetailed data analysis of the H 2 neutron spectra,along with implementation of both semiclassical andquantum calculations of the expected intramoleculardynamics [1], distinctly showed the superiority of thequantum-mechanical models. An example is shownin Fig. 1 b). The agreement found between measuredand quantum-calculated spectra, makes H 2 aconvenient fluid reference sample, particularly suitedto small-angle experiments, and, more generally, toinvestigations where the similarity between thegeometrical configuration of a liquid sample insideacontainer and the employed normalization standardis crucial.The hydrogen calibration technique becomes evenmore powerful in the case of two-dimensionaldetection at small angles, as for the new BRISPspectrometer [2]. The availability of a referencesample characterized by a broad energy spectrumlike H 2, and the detailed knowledge of its scatteringlaw for each (E 0, E f, θ)-triplet, E 0 and θ being theincident neutron energy and scattering angle, allowsfor an accurate “cell-by-cell” normalization ofexperimental intensities. Individual normalizationfactors, depending on specific scattering angle θ,solid angle ∆Ω, and efficiency ε, can now be assignedto the sample intensities, for each E value and foreach detector element (see an example subdivisionin Fig. 1 c), with unprecedented accuracy.References[1] E. Guarini, A. Orecchini, F. Formisano, F.Demmel, C. Petrillo, F. Sacchetti, U. Bafile, and F.Barocchi, J. Phys.: Condens. Matter 17, 7895(2005).[2] D. Aisa et al., Nucl. Instr. Meth. A 544, 620(2005).AuthorsF. Barocchi, U. Bafile, F. Formisano, E. Guarini, A.Orecchini, C. Petrillo, F. Sacchetti,Dipartimento di Fisica, Università di Firenze CRS-SOFT, CNR IFAC, OGG Grenoble CRS-SOFT,Dipartimento di Fisica, Università di Perugia, CRS-SOFTSOFT Scientific Report 2004-06104

Effect of Solvent and of Confinement on the Dynamics ofHydrated ProteinsThe studies on protein dynamics mostly focused onthe effect of the chemical and physical environmentson the dynamics and the ‘flexibility’ of thebiomolecules. They have involved the use of nonfully aqueous solvents, of confining media (poroussilica hydrogels and saccharide ‘coatings’) and ofmedium to high pressures. The molecular flexibilityof enzymes may be controlled by properly choosingthe physical and chemical properties of theenvironment around the protein. This perspectivehas a number of practical consequences on thebiological, food science and pharmaceutical fields. Anelastic scattering study of the mean square atomicfluctuations of lysozyme in water-glycerol mixturesshowed that the environment rules the proteindynamical transition. Above a certain threshold valuelocated approximately at 0.1 hydration, the thermalstability of lysozyme in glycerol progressivelydecreases. At the same time, the protein internaldynamics as measured by the atomic mean squaredisplacement shows a marked onset. Such a resultseems to confirm that protein flexibility is inverselycorrelated to thermal stability.Several studies in the recent literature have beenaddressed to the relevance of the interactionsbetween the external medium and the proteinsurface in determining the internal protein dynamics.In this respect the study of the dynamic properties ofproteins embedded in saccharide glasses has provento be a most useful experimental approach. Indeed,this is a strategy exploited, in nature, by someorganisms which replace water by a glass formingsolvent. This enables these organisms to affordadverse conditions, like high temperatures orextreme drought, in a state of suspended animationcalled anhydrobiosis. Elastic neutron scatteringmeasurements were performed in the temperaturerange 20-340 K on samples obtained by dryingeither MbCO-trehalose-H 2O or MbCO-trehalose-D 2Osolution, and then by re-hydrating in a 75% relativehumidity D 2O atmosphere. The hydrogen atom meansquare displacements thus obtained indicate that inthe trehalose-water solid glasses or amorphousplasticized systems each component looses itsindividuality becoming a collective system.In view of forthcoming studies on the dynamics ofproteins embedded in porous media, the dynamics ofthe water solvent has been investigated underconfining conditions in silica hydrogels performingelastic temperature scans. The obtained meansquare hydrogen displacements (MSD) point out thatwater in cryogenic conditions is in an amorphousstate and a dynamic glass-like transition around 200K can be evidenced. Test experiments were alsocarried out to investigate the pressure dependenceof the atomic fluctuations in small globular proteins(lysozyme and trypsin). The investigation wascarried out in a pressure range (1 – 2000 bar) belowthe cold denaturation limit having thus enzymes thatwere still biologically active. The MSD data show onlysmall variations with pressure that are howevercoherent with the results of QENS experiments thatshow a small reduction of the volume accessed bythe protons with increasing pressure.Fig. 1. Mean square fluctuation for the two systems,at the high concentration, in the range oftemperature 275 K – 310 K tot/61.61.41.21.00.80.60.40.20.00 50 100 150 200 250 300T (K)Fig. 2. Temperature dependence of the MSDobtained using the gaussian model (eq. 1). ● =Encapsulated Mb; = Mb powder. Continuous line:harmonic contribution of the MSD.AuthorsA. Gliozzi, R. Rolandi, Università di Genova, S.Magazù, U. Wanderlingh, Università di Messina, M.Corti, L. Cantù, Univ. Milano, R. Cordone, A.Cupane,Università di Palermo, A. Deriu Università di Parma,G. Onori, A. Paciaroni Università di Perugia, CRS-SOFT, A. Congiu Castellano Università di Roma LaSapienza, A. Filabozzi, G. Paradossi Università diRoma Tor Vergata.105SOFT Scientific Report 2004-06

Scientific Report – Elastic and inelastic scattering of neutrons and X-raysDynamics in Model Membranes, Membrane-Protein andMembrane-DNA InteractionsThe dynamics of different model membranes wasstudied in detail. A first study concerned thedynamics of sugar-based anphiphilic molecules(gangliosides) in bilayer domains. Gangliosides areglycosphingolipids abundant in neuronal plasmamembranes, which are believed to be involved inprocesses like protein binding, cell recognition andsignal transduction, while being embedded inmembrane microdomains. These sphingolipidenricheddomains, SED, are lipid-driven, whichmeans that their mechanical properties andbiological functions is strongly determined by thebehaviour of the embedded lipids. As a first step, weinvestigated the influence on both in-plane and outof-planelipid dynamics brought about by thepresence of glycosphingolipids. By spreadingmixtures of GM1-phospholipid solutions onmonocrystalline Si wafers, we were able to obtainoriented mutilayers and thus to in-plane and out-ofplanemotions. Elastic temperature scans wereperformed from cryogenic temperatures, where lipidmotions are essentially harmonic, to the gel-liquidphase transition of the phospholipid, occuring around300 K. No anisotropy in the MSD and no GM1-dependence is observed in the low-T region. Above310 K an abrupt decrease of the elastic intensity isobserved together with a strong anisotropic effect,linked to the presence of the GM1, since it is notdetected in the pure-phospholipid system. SED aremulticomponent systems much more complex thanjust one sphingolipid plus one ganglioside. The futureaim is to progressively approach the situation of areal membrane, both from the lipid and the proteinside.The interaction of lipid bilayers with otherbiomolecular species (proteins and nucleic acids) wasalso investigated. Highly oriented DMPA phospholipidmultilayers with physiological amounts of animportant membrane protein, myelin basic protein(MBP), were prepared with a technique analogous tothat previously described. MBP is the second majorprotein of myelin, a discontinuous multi-bilayermembrane sheath wrapped around the nerve axon.The integrity of the myelin sheath is fundamental tooptimise the action potential conduction along theaxon. Stacking abnormalities occur in the presenceof severe demyelinating diseases like multiplesclerosis. Therefore, it is of outermost importance tounderstand the nature of the interactions thatmaintain structural and dynamical integrity. Presenceof MBP induces a significant increase of MSD,particularly in the out-of-plane direction. In otherwords, the presence of the protein seems to increasethe diffusion volume accessible to protons in theinterfacial hydrophilic region, therefore allowingprotons to increase their displacement in the out-ofplanedirection. This could be due to inter-digitationof part of the protein into the lipid headgroups, or tothe penetration of some hydrophobic segments intothe acyl-chains, thus decreasing the energy barriersbetween the hydrophobic and hydrophilic regions ofthe bilayer itself. This interpretation is suggested bythe fact that both inter-digitation, and monolayerintercalation have been observed in the fluid phase.Interestingly, NMR studies suggested that the lipidacyl chains are more mobile in the presence of MBPpossibly as a result of protein-induced reorganizationof lipid headgroups.Highly oriented lamellar DOTAP-DOPC modelmembranes have also been studied as a function ofthe DOPC/(DOPC + DOTAP) molar weight ratio,and of the cationic lipid/DNA molar weight ratio.The main result of the elastic scattering experimentsis that a minimum amount of DNA phosphate groupsis not sufficient to induce modifications in membranedynamics. On the other hand, at the isoelectric point,the balance of the total net charge inside thecomplex, together with the displacement of boundwater molecules into solution provides new degreesof freedom to the lipoplex, enhancing the apolarregion fluidity and resulting in a very large increaseof the out-of-plane lipid motions. (Å 2 )0.60.40.20.00.60.40.20.00.60.40.2b)0.0c)0 50 100 150 200 250 300T (K)Fig. 1. Normalised mean square displacements ofthe CLs-DNA mixed multilayers vs T, obtained in theframework of the Gaussian model. Panel a): Lipids;panel b): = 4; panel c): iso = 2.2. Opensquares: out-of-plane direction; filled circles: inplanedirection.AuthorsA. Gliozzi, R. Rolandi, Università di Genova, S.Magazù, U. Wanderlingh, Università di Messina, M.Corti, L. Cantù, Univ. Milano, R. Cordone, A.Cupane,Università di Palermo, A. Deriu Università di Parma,G. Onori, A. Paciaroni Università di Perugia, CRS-SOFT, A. Congiu Castellano Università di Roma LaSapienza, A. Filabozzi, G. Paradossi Università diRoma Tor Vergata.a)SOFT Scientific Report 2004-06106

Dynamics of Hydrated Saccharides and Saccharide GelsCarbohydrates are present in a wide range ofbiological assemblies; the interest on their dynamicalproperties arises not only for basic biophysicalstudies, but also in view of application-orientedinvestigations. Modern approaches to food sciencegive an increasing relevance to dynamic molecularproperties: it has been pointed out that hydrationwater is in dynamically constrained glassy state,rather than in equilibrium thermodynamic phase.Concepts borrowed from synthetic polymer scienceas for instance that of dynamical glass-liketransitions, are now currently applied in ‘‘foodpolymer science’’.Studies on the dynamics of polysaccharide extractedfrom starch (amylose, amylopectin, and theoligomeric building block, glucose) have beenperformed on IN13. They have shown that in the lowhydration regime (up to at least h » 0.6 w/w) waterinduces a kinetic transition, similar to that observedin proteins at similar hydration level. The differentbehaviour of the hydration dependence of the MSD inglucose, amylose, and amylopectine can be tracedback to the specific features of the hydration processWhen hydrated, amylose chains give rise to doublehelical secondary structures. Their regular packinginto hexagonal superstructures, kept together byextra-chain hydrogen bonds (HB), leave a largecentral pore of an average diameter of about 19 Å,into which several water molecules can beaccommodated. During hydration, H 2O moleculesgradually fill the pore up to a saturation point whichcan be located at a water content of about 27%.Our data on the hydration dependence of the meansquare fluctuation support this picture. For amyloseand amylopectin an almost linear increase of theMSD with hydration is observed up to h ~ 0.3, i.e. inthe regime where water fills the pores. Above thishydration value, water molecules that are furtheradded are located outside the pores, and they giveup to a progressive swelling of the sample.Elastic incoherent neutron scattering experimentswere also performed on trehalose-, maltose-,sucrose-H 2O mixtures. The decrease in the elasticintensity above the dynamical ‘glass-like’ transition isless marked in the case of trehalose-water mixturethan for the other disaccharide-water mixtures. Thisresult indicates that trehalose has a larger structuralresistance to temperature changes and a higher“rigidity” in comparison with maltose and sucrose,the latter showing the “softest” dynamic behaviour.The trehalose-H 2O mixture is therefore characterizedby a lower fragility namely by a higher resistance tolocal structural changes when temperature decreasestowards the glass transition value. The “stronger”character of trehalose-H 2O mixture justifies its betterattitude, with respect to maltose and sucrose-H 2Omixtures to encapsulate biostructures in a more rigidmatrix. The effect of the interplay between waterand hydrophilic polymer matrices on the dynamics ofconfined water has also been studied. A detaileddescription of localized diffusive motions in waterand in the polymer moiety is of relevance since, inhydrophilic polymeric networks, they are coupledwith permeation of drug molecules in controlleddelivery functions. A quantitative knowledge of thecorrelation of dynamic parameters with structuralfeatures of the network is necessary for the design ofefficient drug delivery systems. Elastic neutronscattering measurements have been performed onchemically cross-linked polysaccharide matrices(sephadex) at fixed hydration degree, and in atemperature range from 0 to 50 C. These matricesare characterized by a very narrow pore sizedistribution and it is thus possible to study the effectof the pore size on the dynamics of confined solvent.The picture emerging from this investigation is thatof hydration water that behaves differently accordingto the pore size. In the future similar will beextended to more biologically relevant randomnetwork systems.These studies have been carried out as collaborativeprojects between the CRG-IN13 local team (F. Natali,L. Bove, D. Russo, M. Tehei) and several Italianresearch groups.M5004003002001000Sucrose+19H 2OMaltose+19H 2OTrehalose+19HSucrose+19D 2O2OTrehalose+19D 2OSucrose+6H 2OTrehalose+6H 2OTrehalose SucrosePBB 2O 3GlycerolO-terphenylSelenium20 40 60 80 100 120mAuthorsA. Gliozzi, R. Rolandi, Università di Genova, S.Magazù, U. Wanderlingh, Università di Messina, M.Corti, L. Cantù, Univ. Milano, R. Cordone, A.Cupane,Università di Palermo, A. Deriu Università di Parma,G. Onori, A. Paciaroni Università di Perugia, CRS-SOFT, A. Congiu Castellano Università di Roma LaSapienza, A. Filabozzi, G. Paradossi Università diRoma Tor Vergata107SOFT Scientific Report 2004-06

Projects and CollaborationsSOFT Scientific Report 2004-06108

Projects and CollaborationsExternal fundsPRIN 2005DINAMICA VIBRAZIONALE E FENOMENI DI RILASSAMENTO IN SISTEMI DISORDINATINational responsible: G. VilianiLocal responsible: G. VilianiLocal fund: 20.500 Euro + 18.500 Euro from Sincrotrone ElettraPRIN 2005FORMAZIONE DI STATI ARRESTATI A BASSA DENSITA' IN NUOVI MATERIALI: RICERCA DI UN PARADIGMAUNIFICANTE NEI PROCESSI DI GELIFICAZIONE COLLOIDALE, PROTEICA E MOLECOLARENational responsible: Francesco SciortinoLocal responsible: Francesco SciortinoLocal fund: MIUR 60.000 EURO, University 25.800 Euro.PRIN 2005DYNAMIC ARREST AT LOW DENSITY IN SOFT MATERIALS: SEARCH FOR A UNIFYING PARADIGM TO DESCRIBE GELFORMATION IN COLLOIDAL DISPERSIONSNational responsible: Francesco SciortinoLocal responsible: Cecilia M.C. GambiLocal fund: 40.000 EuroPRIN 2005STATI ARRESTATI IN MATERIA SOFFICE A BASSA DENSITÀ: GELIFICAZIONE IN SISTEMI MACROMOLECOLARI DITIPO STEP-POLYMERNational responsible: Francesco sciortinoLocal responsible: Daniele FiorettoLocal fund: 60.000 EuroPRIN 2005AGING, FLUCTUATION AND RESPONSE IN OUT-OF-EQUILIBRIUM GLASSY SYSTEMSNational responsible: Dino LeporiniLocal responsible: Dino LeporiniGlobal funds: 188.000 Eur, Local funds: 52.000 Eur.PRIN 2005AGING, FLUCTUATION AND RESPONSE IN OUT-OF-EQUILIBRIUM GLASSY SYSTEMSNational responsabile: Dino LeporiniLocal responsible: Renato TorreLocal fund: 44.000 EuroPRIN 2005AGING, FLUCTUATION AND RESPONSE IN OUT-OF-EQUILIBRIUM GLASSY SYSTEMSNational responsabile: Dino LeporiniLocal responsible: Giancarlo RuoccoLocal fund: 73.452 EuroPRIN 2005ROLE OF METALS IN AGGREGATION PROCESSES OF PROTEINS: XAS SPECTROSCOPY AND NUMERICALSIMULATIONS.Local Responsible: Silvia Morantein collaboration with: ITC-CNR - Trento; University of Palermo; University of Cosenza; EMBL-DESY Hamburg-GermanyPAIS 2003-2004LIMADNazional responsible: Luigi Cristofolini,Global funds: 98.000 Euro109SOFT Scientific Report 2004-06

Projects and CollaborationsPAIS 2003-2004HPITNational responsible: Andrea Di CiccoGlobal funds 86.000 EuroFIRB 2001-2006SISTEMI COLLOIDALI CON INTERAZIONI A CORTO RAGGIO: MODELLI PER LA CRISTALLIZAZIONE DI PROTEINENational responsible: Francesco SciortinoLocal fund: MIUR 390.000 EuroFIRB 2003–2005NANODISPOSITIVI MOLECOLARINational responsible: Marco P. FontanaTotal fund: 800.000 EuroFIRB ITALIA ISRAELE 2006-2008DISPOSITIVI OTTICI NANOSTRUTTURATI IN MATERIA SOFFICENational responsible: Giancarlo RuoccoLocal fund: MIUR 300.000 EuroFISR 2003-2006NUME (fuel cells)National responsible: Bruno ScrosatiLocal responsible: Andrea Di CiccoLocal funding: 100.000 EuroProgetto GALILEO Italia-FranciaDISPOSITIVI PER LA GENERAZIONE DI RADIAZIONE THZ MEDIANTE NANO-STRUTTURE OTTICHE PLASMONICHENational responsible: Giancarlo RuoccoTotal fund: 5.300 EuroNode of the The Marie Curie Research/Training Network on Dynamical Arrest - MRTN-CT-2003-504712Principal Investigator: Piero TartagliaLocal fund: Posizione Post-Doc biennaleLaboratorio Regionale 2005-06SIQUALCoordinator prof. R. MarchelliLocal responsible: prof M. P. FontanaTotal fund: 40.000 EuroSOFT Scientific Report 2004-06110

Ongoing European ProjectsWhitin FP6 we partecipaate to the Integrated Infrastructure Iniziative for neutron and muon, called NMI3. Whithinthis iniziative there are two activities devoted to:1) High resolution and high speed 2d solid state neutron detectors2) New manipulating devices, mainly honeycomb like collimators and neutron Zone PlatesThe work on the detector was devoted to two major aspects of the solid state detector development, that is thedevelopment of a new VLSI ASIC to be used s front-end electronics and a new Si sensor for the development of a0.1 mm resolution detector over an area of several square centimeters. In parallel 1d detector with 0.5 mmresolution and maximum counting rate of 10 MHz over an area of 40x70 mm2 is being tested. During 2004 and2005 a first version of the ASIC has been completed and tested obtaining the expected peaking time of 30 ns andthe adequate equivalent noise of 500 e rms.Honeycomb converging collimator, 2m lond, 0.4 degsdivergence.0.250.20.150.10.0500.4-0.2 -0.1 0 0.1 0.2shift (mm)0.30.2The new high resolutionmicrostrip Si sensor.Wafer before cutting anddetail of the sensor pads.The sensor has aresolution of 80 m and640x640 strips.0.10-0.2 -0.1 0 0.1 0.2shift (mm)Response of a single strip coatedwith metal (blue) and oxide (red),converter in front (solid line) andon the back (dashed line) using a1m (left) and 5 m (right) thickconverter. Neutron wavelengthfixed equal to 2 Å. Only the 80 keVelectrons are considered.111SOFT Scientific Report 2004-06

Projects and CollaborationsCollaborationsProf. P. Baglioni (Dip. Chimica, Univ. Firenze)Dr. A. Best, (Max-Planck-Institute für Polymerforschung, Mainz, Germany)Prof. L. Borjessonn (Chalmers Univ., Gotheborg, Sweden)Prof. T. Bryk (Lviv, Ukraina)Dr. A. Chumakov (ESRF, Grenoble, France)Prof. C. Dreyfus (Dep. Phys. Milieux Denses, IMPMC, France)Prof. J. Dyre (Research center “Glass and Time”, Roskilde, Denmark)Dr. G. Foffi (Losanna, Svizzera)Dr. R. Giordano (Dip. Fisica, Univ. Messina)Dr. M. Krisch (ESRF, Grenoble, France)Prof. C. Likos (CODEF, Dusseldorf, Germany)Prof. H. Loewen (CODEF, Dusseldorf, Germany)Dr. A. Madsen (ESRF, Grenoble, France)Dr. M. Martinell (IPCF-CNR, Pisa)Dr. C. Masciovecchio (Elettra, Trieste)Prof. A. Matic (Chalmers Univ., Gotheborg, Sweden)Dr. G. Monaco (ESRF, Grenoble, France)Dr. K.L. Ngai, Dr. R. Casalini, Dr. C.M. Roland (NRL Washington, USA)Prof. A. Pacini (Dip. Anatomia, Univ. Firenze)Prof. T. Pakula (Max-Planck-Institute für Polymerforschung, Mainz, Germany)Prof. M. Paluch, Prof. S. Rzoska Silesian (University, Katowice, Poland)Prof. R. Pick (Univ. P. and M. Curie, Paris, France)Prof. R. Righini (Dip. Chimica, Univ. Firenze)Prof. E.A. Rössler (Universität Bayreuth, Germany)Prof. W. Schirmacher (TU, Munchen, Germany)Dr. F. Sette (ESRF, Grenoble, France)Prof. P. Shurtenberger (Fribourg, Svizzera)Prof. H.W. Spiess (Max-Planck Institut für Polymerforschung, Mainz, Germany)Prof. E. Stanley (Boston University, USA)Prof. F. Starr (Wesleyan, USA)Dr. J. Teixeira (Lab. Leon Brillouin, CEA-CNRS Saclay, France)Dr. S. Yannopoulos (FORTH, Patras, Greece)SOFT Scientific Report 2004-06112

113SOFT Scientific Report 2004-06

DisseminationSOFT Scientific Report 2004-06114

DisseminationThe dissemination of the scientfic results follows the usual routes: paper publications ininternational referred journals, invited and contributed talks to conference, organization ofSchools and workshops (among which the annual Soft meetings) and exchange of Studentsand PostDocs with national and international collaborating groups.PublicationsSoft was particularly successful with publications in its two and half years of life. About 280papers co-authored by Soft members were published in international journals in this period.Many of them appeared in journals with strong impact: we mention for example 36publications in Physical Review Letters, about 55 publications in Physical Review (A, B andE) and three publications in journals with impact factor over-ten: one on PNAS (F. Sciortinoand others, PNAS 102, 16558 (2005)), one on Review of Modern Physics (T. Scopigno et al.RMP 77, 881 (2005)) and one on Nature (M. Santoro, F. Gorelli et al., see below).Worth to mention is the paper by the Soft member D. Leporini (V. Bercu, M. Martinelli, C. A.Massa, L. A. Pardi, D. Leporini, J. Phys.: Cond. Matt. 16, 479 (2004)) that appeared in the“Top Paper 2004 Showcase” of the IOP. This list highlights the leading and most frequentlydownloaded papers from J. Phys.: Cond. Matt.Also worth to mention is the discovery, published on Nature (M. Santoro, F. A. Gorelli, R.Bini, G. Ruocco, S. Scandolo, W. Crichton, Nature 441, 857 (2006)), of the amorphoussilica-like carbon dioxide. This discovery received a large press coverage and the paper hasbeen commented in a News & Views article on Nature.115SOFT Scientific Report 2004-06

DisseminationWe also point out the paper by the Soft researcher R. Di Leonardo (PRL 96, 134502 (2006))on the application of the holographic tweezers to microfluidic velocimetry that also receiveda mention on Nature (Research Highlights, Nature 440, 973 (2006)).Finally, as most cited paper among the 2005 Soft publication, we mention the PRL article:E. Zaccarelli, S. V. Buldyrev, E. La Nave, A. J. Moreno, I. Saika-Voivod , F. Sciortino,P. Tartaglia. Model for reversible colloidal gelation. PRL 94, 218301 (2005).The following list reports the whole body of Soft publications, separated by year andordered alphabetically according to the first author’s name.2004A. Andronico, L. Angelani, G. Ruocco, F. Zamponi.Topological properties of the mean field φ 4 model.Physical Review E 70, 041101 (2004).L. Angelani, C. De Michele, G. Ruocco, F. Sciortino.Saddles and softness in simple model liquids.Journal of Chemical Physics 121, 7533 (2004).V. Bavastrello, E. Stura, S. Carrara, V. Erokhin, C. Nicolini.Poly(2,5-dimethylaniline)-MWNTs nanocomposite:A new material for conductometric acid vapours sensor.Sensors and Actuators B 98, 247 (2004).V. Bavastrello, V. Erokhin, S. Carrara, F. Sbrana, D. Ricci, C. Nicolini.Morphology and conductivity in poly(ortho-anisidine)/carbon nanotubes nanocomposite films.Thin Solid Films 468, 17 (2004).V. Bercu, M. Martinelli, C. A. Massa, L. A. Pardi, D. Leporini.A study of the deep structure of the energy landscape of glassy polystyrene:The exponential distribution of the energy barriers revealed by high-fieldelectron spin resonance spectroscopy.Journal of Physics: Condensed Matter 16, 479 (2004).A. Bonincontro, C. Cametti.Interfacial characterization of mesoscopic particle suspensionsby means of radiowave dielectric spectroscopy: a minireview.Colloids and Surfaces A 246, 115 (2004).A. Bonincontro, G. Onori.Investigation by dielectric spectroscopy of domain motions in lysozyme:effect of solvent and binding of inhibitors.Chemical Physics Letters 398, 260 (2004).F. Bordi, C. Cametti, R. H. Colby.Dielectric spectroscopy and conductivity of polyelectrolyte solutions.Journal of Physics: Condensed Matter 16, R1423 (2004).SOFT Scientific Report 2004-06116

F. Bordi, C. Cametti, M. Dociauti, D. Gaudino, T. Gili, S. Sennato.Complexation of anionic polyelectrolyte with cationic liposomes:evidence of reentrant condensation and lipoplex formation.Langmuir 20, 5214 (2004).F. Bordi, M. Prato, O. Cavalleri, C. Cametti, M. Canepa, A. Gliozzi.Azurin self-assembled monolayers characterized electrical impedance spectroscopy andspectroscopic ellipsometry.Journal of Physical Chemistry B 108, 20263 (2004).C. Casieri, L. Senni, M. Romagnoli, U. Santamaria, F. De Luca.Determination of moisture fraction in wood by mobile NMR device.Journal of Magnetic Resonance 17, 364 (2004).L. Comez, S. Corezzi, D. Fioretto, H. Kriegs, A. Best, W. Steffen.Slow dynamics of salol: a pressure-and temperature-dependent light scattering study.Physical Review E 70, 011504 (2004).S. Corezzi, L. Comez, D. Fioretto.Can experiments select the configurational component of excess entropy?European Physics Journal E 14, 143 (2004).L. Cristofolini, M. P. Fontana.Surface viscoelastic behaviour of polymeric Langmuir monolayers.Philosophical Magazine B 84, 1537 (2004).C. De Michele, F. Sciortino, A. Coniglio.Scaling in soft spheres: fragility invariance on the repulsive potential softness.Journal of Physics: Condensed Matter 16, L489 (2004).A. Di Michele, M. Freda, G. Onori, A. Cantucci.Hydrogen bonding of water in aqueous solutions of trimethylamine-N-oxideand tert-bytyl alcohol: a near-infrared pectroscopy study.Journal of Chemical Physics 120, 6145 (2004).V. Erokhin, T. Berzina, M. P. Fontana.Electron beam irradiation for structuring of molecular assemblies.IEEE Transaction Nanobioscience 3, 6 (2004).S. Erokhina, T. Berzina, L. Cristofolini, D. Shchukin,G. Sukhorukov, L. Musa, V. Erokhin, M. P. Fontana.Patterned arrays of magnetic nano-engineered capsules on solid supports.Journal of Magnetism and Magnetic Materials 272-276, 1353 (2004).E. Fabiani, L. Bove, A. Fontana, O. Pilla, C. Petrillo.Dynamic structure factor of vitreous germania.Physica B 350, 1099 (2004).M. P. Fontana, R. Burioni, D. Cassi.Generalized Peierls-Landau instability: a novel perspective on the nature of glasses?Philosophical Magazine B 84, 1307 (2004).G. Foffi, F. Sciortino , E. Zaccarelli, P. Tartaglia.Dynamical arrest in dense short-ranged attractive colloids.Journal of Physics: Condensed Matter 16, 3889 (2004).117SOFT Scientific Report 2004-06

DisseminationF. A. Gorelli, V. M. Giordano, P. R. Salvi, R. Bini.Linear carbon dioxide in the high-pressure-high-temperature crystalline phase IV.Physical Review Letters 93, 205503 (2004).G. Gubbiotti, M. Kostylev, N. Sergeva , M. Conti,G. Carlotti, T. Ono, A. N. Slavin, A. Stashkevich.Brillouin light scattering investigation of magnetostatic insymmetric and asymmetric NiFe/Cu/NiFe trilayered wires.Physical Review B 70, 224422 (2004).E. La Nave, F. Sciortino.On static and dynamic heterogeneities in water.Journal of Physical Chemistry B 108, 19663 (2004).M. A. Macri’, G. Garreffa, F. Giove, M. Guardati, A. Ambrosini, C. Colonnese, B. Maraviglia.In vivo quantitative 1 H MRS of cerebellum and evaluation of quantitationreproducibility by simulation of different levels of noise and spectral resolution.Magnetic Resonance Imaging 22, 1385 (2004).C. Masciovecchio, A. Gessini, S. Di Fonzo, L. Comez, S. C. Santucci, D. Fioretto.Inelastic ultraviolet scattering from high frequency acoustic modes in glasses.Physical Review Letters 92, 247 (2004).S. Mossa, F. Sciortino, P. Tartaglia, E. Zaccarelli.Ground-state clusters for short-range attractive and long-range repulsive potentials.Langmuir 20, 10756 (2004).G. Parisi, G. Ruocco, F. Zamponi.Fragility in p-spin models.Physical Review E 69, 061505 (2004).O. Pilla, S. Caponi, A. Fontana, M. Montagna, F. Rossi,G. Viliani, L. Angelani, G. Ruocco, G. Monaco, F. Sette.The low energy excess of vibrational states in vSiO 2 : the role of transverse dynamics.Journal of Physics: Condensed Matter 16, 8519 (2004).D. Pisignano, T. Berzina, V. Erokhin, M. P. Fontana,A. Della Torre, P. Visconti, R. Rinaldi.High-sensitive ultrathin negative electron beam resistbased on Langmuir-Blodgett films of polycyanoacrylate.Japanes Journal of Applied Physics 43, 3984 (2004).G. Ruocco, F. Sciortino, F. Zamponi, C. De Michele, T. Scopigno.Landscapes and fragilities.Journal of Chemical Physics 120, 10666 (2004).B. Ruzicka, L. Zulian, G. Ruocco.Routes to gelation in a clay suspsension.Physical Review Letters 93, 258301 (2004).I. Saika-Voivod, F. Sciortino.Phase Diagram of silica from computer simulation.Physical Review E 70, 061507 (2004).SOFT Scientific Report 2004-06118

I. Saika-Voivod, F. Sciortino.Distributions of inherent structure energies during aging.Physical Review E 70, 041202 (2004).I. Saika -Voivod, E. Zaccarelli, F. Sciortino, S. V. Buldyrev, P. Tartaglia.Effect of bond lifetime on the dynamics of a short- range attractive colloidal system.Physical Review E 70, 041401 (2004).F. Scarponi, L. Comez, D. Fioretto, L. Palmieri.Brillouin light scattering from transverse and longitudinal acoustic waves in glycerol.Physical Review B 70, 054203 (2004).S. Sennato, F. Bordi, C. Cametti.Correlated adsorption of polyelectrolytes in the charge inversion of colloidal particles.Europhysics Letters 68, 296 (2004).S. Sennato, F. Bordi, C. Cametti.On the phase diagram of reentrant condensation in polyelectrolyte-liposome complexation.Journal of Chemical Physics 121, 4936 (2004).V. Troitsky, T. Berzina, D. Shchukin, G. Sukhorukov, V. Erokhin, M. P. Fontana.Simple method of hydrophilic/hydrophobic patterning of solid surfacesand its application to self-assembling of nanoengineered polymeric capsules.Colloids and Surfaces A 245, 163 (2004).L. Valkova, N. Borovkov, O. Koifman, A. Kutepov,T. Berzina, M. P. Fontana, R. Rella, L. Valli.Sorption of amines by the Langmuir–Blodgett films of soluble cobaltphthalocyanines: evidence for the supramolecular mechanisms.Biosensors and Bioelectronics 20, 1177 (2004).E. Zaccarelli, F. Sciortino, P. Tartaglia.Numerical study of the glass-glass transition in short-ranged attractive colloids.Journal of Physics: Condensed Matter 16, S4849 (2004).2005M. Alagia, C. Baldacchini, M. G. Betti, F. Bussolotti,V. Carravetta, U. Ekström, C. Mariani, S. Stranges.Core-shell photo-absorption and photoelectron spectraof gas-phase pentacene: experiment and theory.Journal of Chemical Physics 122, 124305 (2005).M. Alesiani, F. Proietti, S. Capuani, M. Paci, M. Fioravanti, B. Maraviglia.13 C CPMAS NMR spectroscopic analysis applied to wood characterization.Applied Magnetic Resonance 29, 177 (2005).L. Angelani, L. Casetti, M. Pettini, G. Ruocco, F. Zamponi.Topology and phase transition: from an exactly solvable modelto a relation between topology and thermodynamics.Physical Review E 71, 036152 (2005).119SOFT Scientific Report 2004-06

DisseminationL. Angelani, G. Foffi, F. Sciortino, P. Tartaglia.Diffusivity and configurational entropy maxima in short-range attractive colloids.Journal of Physics: Condensed Matter 17, L113 (2005).L. Angelani, G. Ruocco, F. Zamponi.Relationship between phase transition and topological changes in one dimensional models.Physical Review E 72, 016122 (2005).R. Angelini, P. Giura, C. Henriquet, G. Monaco, R. Verbeni, G. Ruocco, F. Sette.Sample environment and experimental set-up for inelastic x-ray scatteringmeasurements of liquid hydrogen fluoride and HF x H 2 O 1-x solutions.Review of Scientific Instruments 76, 013905 (2005).R. Angelini, P. Giura, G. Monaco, G. Ruocco, F. Sette.Relaxation dynamics in HF x H 2 O 1-x solutions.Journal of Chemical Physics 123, 034502 (2005).G. Baldi, S. Caponi, L. Comez, S. Di Fonzo, D. Fioretto, A. Fontana, A. Gessini,C. Masciovecchio, M. Montagna, G. Ruocco, S. C. Santucci, G. Viliani.Brillouin ultraviolet light scattering on vitreous silica.Journal of Non-Crystalline Solids 351, 1919 (2005).M. Bellini, C. Cavalieri, C. Corsi, R. Eramo, M. Materazzi.Mutually coherent high-order harmonic pulses for XUV Ramsey spectroscopy .Laser Physics 15, 324 (2005).P. Benassi, S. Caponi, R. Eramo, A. Fontana, A. Giugni, M. Nardone, M. Sampoli, G. Viliani.Sound attenuation in a unexplored frequency region:Brillouin ultraviolet light scattering measurements in v-SiO 2 .Physical Review B 71, 172201 (2005).V. Bercu, M. Martinelli, C. A. Massa, L. A. Pardi, D. Leporini.Signatures of the fast dynamics in glassy polystyrene:first evidence by high-field electron paramagnetic resonance of molecular guests.Journal of Chemical Physics 123, 174906 (2005).V. Bercu, M. Martinelli, C. A. Massa, L. A. Pardi, D. Leporini.The onset of the fast dynamics in glassy polystyrene observed by the detrappingof guest molecules: a high-field electron paramagnetic resonance study.Europhysics Letters, 72, 590 (2005).A. Bonincontro, C. Cametti, K. H. Nierhaus, M. G. Ortore, G. Risuleo.Ribosomes deprived of select proteins show similar structuralalterations induced by thermal treatment of native particles.Cellular Biochemistry and Biophysics 42, 55 (2005).A. Bonincontro, S. Marchetti, G. Onori, A. Rosati.Interaction cetyltrimethyammonium bromide-DNA investigated by dielectric spectroscopy.Chemical Letters 312, 55 (2005).A. Bonincontro, G. Risuleo.Structural studies of E.coli ribosomes by spectroscopic techniques: a specialization review.Spectrochimica Acta A 62, 1070 (2005).SOFT Scientific Report 2004-06120

F. Bordi, C. Cametti, M. Dociaiuti, S. Sennato.Large equilibrium clusters in low-density aqueous suspensionsof polyelectrolyte-liposome complexes: a phenomenological model.Physical Review E 71, 050401R (2005).F. Bordi, C. Cametti, T. Gili, S. Sennato, S. Zuzzi, S. Dou, R. H. Colby.Conductometric properties of linear polyelectrolytesin poor-solvent conditions: the necklace model.Journal of Chemical Physics 122, 234906 (2005).F. Bordi, C. Cametti, T. Gili, S. Sennato, S. Zuzzi, S. Dou, R. H. Colby.Solvent quality influence on the dielectric propertiesof polyelectrolyte solvent: A scaling approach.Physical Review E 72, 031806 (2005).F. Bordi, C. Cametti, C. Marianecci, S. Sennato.Equilibrium particle aggregates in attractive colloidal suspensions.Journal of Physics: Condensed Matter 17, S3423 (2005).F. Bordi, C. Cametti, S. Sennato.Polyions act as an electrostatic glue for mesoscopic particles aggregates.Chemical Physics Letters 409, 134 (2005).L. E. Bove, E. Fabiani, A. Fontana, O. Pilla, F. Paoletti, C. Petrillo, I. C. Vieiro-Bento.Brillouin neutron scattering of v-GeO 2 .Europhysics Letters 71, 563 (2005).G. Briganti, G. D'Arrigo, M. Maccarini, C. Pierleoni, F. Sterpone.Hydration and thermodynamic equilibrium of nonionic surfactant in solution.Colloids and Surfaces A 261, 93 (2005).R. Buffa, S. Cavalieri, R. Eramo, L. Fini .Coherent control of third-harmonic generation and multiphotonionization: experimental and theoretical studies.Laser Physics 15, 334 (2005).S. Capaccioli, D. Prevosto, M. Lucchesi, P. Rolla, R. Canalini, K. Ngai.Identifying the genuine Johari-Goldstein beta-relaxationby cooling compressing and aging small molecular glass-formers.Journal of Non-Crystalline Solids 351, 2643 (2005).S. Capaccioli, K. Ngai.Relation between the a-relaxation and Johari-Goldstein b-relaxationof a component in binary miscible mixtures of glass-formers.Journal of Physical Chemistry B 109, 9727 (2005).S. Capuani, C. Rossi, M. Alesiani, B. Maraviglia.Diffusion tensor imaging to study anisotropy in a particularporous system: The trabecular bone network .Solid State Nuclear Magnetic Resonance 28, 266 (2005).C. Caronna, F. Natali, A. Cupane.Incoherent elastic and quasi-elastic neutron scatteringinvestigation of hemoglobin dynamics.Biophysical Chemistry 116, 219 (2005).121SOFT Scientific Report 2004-06

DisseminationC. Casieri, F. De Luca, P. Fantazzini.Pore-size evaluation by single-sided nuclear magnetic resonance measurements:compensation of water self-diffusion effect on transverse relaxation.Journal of Applied Physics 97, 043901 (2005).F. Cesarone, M. Caputo, C. Cametti.Memory formalism in the passive diffusion across highly heterogeneous systems.Journal of Membrane Science 250, 79 (2005).S. H. Chong, A. J. Moreno, F. Sciortino, W. Kob.Evidence for the weak steric hindrance scenarioin the supercooled-state reorientational dynamics.Physical Review Letters 94, 215701 (2005).S. G. Chiuzbaian, G. Ghiringhelli, C. Dallera, M. Grioni,P. Amann, X. Wang, L. Braicovich, L. Patthey.Localized Electronic Excitations in NiO Studied with ResonantInelastic X-Ray Scattering at the Ni M Threshold: Evidence of Spin Flip.Physical Review Letters 95, 197402 (2005).L. Ciabini, F. A. Gorelli, M. Santoro, R. Bini, V. Schettino, M. Mezouar.High-pressure and high-temperature equation of state and phase diagram of solid benzene.Physical Review B 72, 094108 (2005).L. Comez, S. Corezzi, G. Monaco, R. Verbeni, D. Fioretto.Ergodic to nonergodic transition in liquids with a local order: the case of m-toluidine.Physical Review Letters 94, 155702 (2005).C. Conti.Complex light: dynamic phase transitions of a light beamin a nonlinear nonlocal disordered medium.Physical Review E 72, 066620 (2005).C. Conti, M. Peccianti, G. Assanto.Spatial solitons and modulational instability in the presenceof large birefringence: The case of highly nonlocal liquid crystals.Physical Review E 72, 066614 (2005).C. Conti, G. Ruocco, S. Trillo.Optical spatial solitons in soft matter.Physical Review Letters 95, 183902 (2005).S. Corezzi, D. Fioretto, J. M. Kenny.Clustering and cooperative dynamics in a reactive system.Physical Review Letters 94, 065702 (2005).S. Corezzi, L. Palmieri, J. M. Kenny, D. Fioretto.Clustering, glass transition and gelation in a reactive fluid.Journal of Physics: Condensed Matter 17, S3557 (2005).E. Cornicchi, G. Onori, A. Paciaroli.Pisecond-time-scale fluctuations of proteins in glassy matrices: the role of viscosity.Physical Review Letters 95, 157804 (2005).SOFT Scientific Report 2004-06122

S. Cozzolino, L. Galantini, C. Leggio, N. V. Pavel.Correlation between small-angle X-ray scattering spectra and apparent diffusion coefficientin the study of structure and interaction of sodium tauroddeoxycholate micelles.Journal of Physical Chemistry B 109, 6111 (2005).L. Cristofolini, M. P. Fontana, C. Boga, O. Konovalov.Microscopic structure of cristalline Langmuir monolayer of hydroxystearic acidsby X-ray reflectivity and GID: OH group position and dimensionality effects.Langmuir 21, 11213 (2005).C. Dallera, E. Annese, J.-P. Rueff, M. Grioni, G. Vankó, L. Braicovich,A. Barla, J.-P. Sanchez, R. Gusmeroli, A. Palenzona, L. Degiorgi, V. Lapertot.Intermediate valence behavior under pressure: how preciselycan we probe it by means of resonant inelastic x-ray emission.Journal of Physics: Condensed Matter 17, S849 (2005).C. Dallera, L. Braicovich, L. Duò, A. Palenzona,G. Panaccione, G. Paolicelli, B. C. C. Cowie, J. Zegenhagen.Hard X-ray photoemission spectroscopy:sensitivity to depth, chemistry and orbital character.Nuclear Instruments and Methods A 547, 113 (2005).F. De Pasquale, C. Testa, R. Soldaini, C. Casieri, F. Podo, F. De Luca.Bayesian analysis of in vivo dynamic C-13-edited H-1 images.Magnetic Resonance Imaging 23, 577 (2005).A. Di Biasio, C. Cametti.Effect of the shape of human erythrocytes on the evaluationof the passive electrical properties of the cell membrane.Bioelectrochemistry 65, 163 (2005).A. Di Falco, C. Conti, G. Assanto.Transient-mode excitation, terahertz generationand wavelength shifting in a photonic band gap.Applied Physics B 81, 415 (2005).C. Di Giulio, G. Bianchi, M. Cacchio, L. Artese, C. Rapino, M. A. Macri’, C. Di Ilio.Oxygen and life span: chronic hypoxia and hyperoxiaas models of study for VEGF, NOS and HIF during aging.Respiration Physiology & Neurobiology 147, 31 (2005).R. Di Leonardo, F. Ianni, G. Ruocco.Aging under shear: structural relaxation of a non-Newtonian fluid.Physical Review E 71, 011505 (2005).R. Di Leonardo, F. Ianni, G. Ruocco.Flow between rotating finite disks with closed-endcondition studied by heterodyne photocorrelation.Journal of Fluid Mechanics 525, 27 (2005).V. Erokhin, S. Carrara, C. Paternolli, L. Valkova, S. Bernstroff, C. Nicolini.X-ray study of structural reorganization in phthalocyaninecontaining Langmuir-Blodgett heterostructures.Applied Surface Science 245 , 369 (2005).123SOFT Scientific Report 2004-06

DisseminationM. Finazzi, M. Portalupi, A. Brambilla, L. Duò,G. Ghiringhelli, F. Ciccacci, M. Zacchigna, M. Zangrando.Chemical effects at the buried NiO/Fe(100) interface.Physical Review B 70, 235420 (2005).G. Foffi, C. De Michele, F. Sciortino, P. Tartaglia.Scaling and dynamics with the range of interaction in short-range attractive colloids.Physical Review Letters 94, 078301 (2005).G. Foffi, C. De Michele, F. Sciortino, P. Tartaglia.Arrested phase separation in a short-ranged attractive colloidal system: a numerical study.Journal of Chemical Physics 122, 224903 (2005).C. M. C. Gambi, R. Giordano, A. Chittofrati, R. Pieri, P. Baglioni, J. Teixeira.Small-angle neutron scattering of ionic perfluoropolyethermicellar solutions: role of counterions and temperature.Journal of Physical Chemistry B 109, 8592 (2005).L. Gavioli, M. Fanetti, M. Sancrotti, M. G. Betti,Long-range-ordered pentacene chains assembled on the Cu(119) vicinal surface.Physical Review B 72, 035458 (2005).N. Giovambattista, C. A. Angell, F. Sciortino, H. E. Stanley.Structural relaxation in the glass transition region of water.Physical Review E 72, 011203 (2005).N. Giovambattista, H. E. Stanley, F. Sciortino.Phase diagram of amorphous solid water: low density,high density, and very high density: amorphous ices.Physical Review E 72, 031510 (2005).N. Giovambattista, H. E. Stanley, F. Sciortino.Relation between the high density phase and thevery-high density phase of amorphous solid water.Physical Review Letters 94, 107803 (2005).L. Giovannini, S. Tacchi, G. Gubbiotti, G. Carlotti, F. Casoli, F. Albertini.Brillouin light scattering study of exchange-coupled Fe/Co magnetic multilayers.Journal of Physics: Condensed Matter 17, 6483 (2005).A. Giuliani, F. Zamponi, G. Gallavotti.Fluctuation relation beyond linear response theory.Journal of Statistical Physics 119, 909 (2005).E. Guarini, U. Bafile, F. Barocchi, F. Demmel, F. Formisano, M. Sampoli, G. Venturi.Collective excitations in liquid CD 4 : neutron scattering and molecular dynamics simulations.Europhysics Letters 72, 969 (2005).E. Guarini, A. Orecchini, F. Formisano, F. Demmel,C. Petrillo, F. Sacchetti, U. Bafile, F. Barocchi.Self dynamics of hydrogen gas as probed by means of inelastic neutron scattering.Journal of Physics: Condensed Matter 17, 7895 (2005).SOFT Scientific Report 2004-06124

G. Gubbiotti, G. Carlotti, T. Okuno, M. Grimditch, L. Giovannini, F. Montocello, F. Nizzoli.Spin dynamics in thin nanometric elliptical Permalloy dots:a Brillouin light scattering investigation as a function of dot eccentricity.Physical Review B 72, 184419 (2005).G. Gubbiotti, G. Carlotti, S. Tacchi, Y. K. Lin, C. Scheck, R. Schad, G. Zangari.Tickness dependance of magnetic anisotropy in epitaxialfilms electrodeposited onto (001) and (011)- GaAS (001).Journal of Applied Physics 97, 10J102 (2005).G. Gubbiotti, S. Tacchi, G. Carlotti, P. Vavassori, N. Singh,S. Goolaup, A. O. Adeyeye, A. Stashkevich, M. Kostylev.Magnetostatic interaction in arrays of nanometric permelloy wires:a magneto-optic Kerr effect and a Brillouin light scattering study.Physical Review B 72, 224413 (2005).M. W. Haverkort, Z. Hu, A. Tanaka, G. Ghiringhelli, H. Roth, M. Cwik,T. Lorenz, C. Schüßler-Langeheine, S. V. Streltsov, A. S. Mylnikova,V. I. Anisimov, C. de Nadai, N. B. Brookes, H. H. Hsieh, H.-J. Lin,C. T. Chen, T. Mizokawa, Y. Taguchi, Y. Tokura, D. I. Khomskii, L. H. Tjeng.Determination of the Orbital Moment and Crystal-Field Splitting in LaTiO 3 .Physical Review Letters 94, 056401 (2005).P. Kumar, S. V. Buldyrev, F. Sciortino, E. Zaccarelli, H. E. Stanley.Static and dynamic anomalies in a repulsive spherical ramp liquid: theory and simulation.Physical Review E 72, 021501 (2005).E. La Nave, F. Sciortino, P. Tartaglia, M. S. Shell, P. G. Debenedetti.Reply to “ Comment on test of nonequilibrium thermodynamicsin glassy systems: the soft-sphere case”.Physical Review E 71, 1033102 (2005).L. Lanzi, M. Carlà, M. Cecilia , M. C. Gambi, L. Lanzi.Dielectric spectroscopy by differential measurements intransmission lines on sodium dodecyl sulfate micelles in water.Journal of Non-Crystalline Solids 351, 2864 (2005).L. Larini, A. Barbieri, D. Prevosto, P. A. Rolla, D. Leporini.Equilibrated polyethylene single-molecule crystals: molecular-dynamics simulationsand analytic model of the global minimum of the free-energy landscape.Journal of Physics: Condensed Matter 17, L199 (2005).L. Larini, D. Leporini.A manifestation of the Ostwald step rule: molecular-dynamics simulations and free energylandscape of the primary nucleation and melting of single molecule polyethylene in solution.Journal of Chemical Physics 123, 144907 (2005).M. Laurati, J. Stellbrink, R. Lund, L. Willner, D. Richter, E. Zaccarelli.Star-like micelles with star-like interaction: a quantitativeevaluation of structure factors and phase diagram.Physical Review Letters 94, 195504 (2005).C. Leggio, L. Galantini, E. Zaccarelli, N. V. Pavel.Small-angle X-ray scattering and light scattering in lysozyme and sodium glycolate micelles.Journal of Physical Chemistry B 109, 23857 (2005).125SOFT Scientific Report 2004-06

DisseminationS. Magazu, F. Migliardo, C. Mondelli, M. Vadala.Correlation between bioprotective effctiveness and dynamic propertiesof trehalose-water, maltose-water and sucrose-water mixtures.Carbohydrate Research 340, 2796 (2005).S. Magazù, F. Migliardo, C. Mondelli, G. Romeo.Inspection of glassy mixture elastic intensity by IN13.Physica Scripta 71, 409 (2005).S. Marchetti, G. Onori, C. Cametti.DNA condensation induced by cationic surfactant: a viscosimetry and DLS study.Journal of Physical Chemistry B 109, 3676 (2005).M. Marconi, A. De Francesco, E. Cornicchi, G. Onori, A. Paciaroni.Hydration and temperature dependent dynamics of lysozymein glucose-water matrices. A neutron scattering study.Chemical Physics 317, 274 (2005).G. Maulucci, M. De Spirito, G. Arcovito, F. Boffi, A. Congiu Castellano, G. Briganti.Particle size distribution in DMPC vesicle solutions undergoing different sonocation times.Biophysical Journal 88, 3545 (2005).S. Melchionna, S. Succi.Lattice Boltzmann-Poisson method for electrorheological nanoflows in ion channels.Computational Physics Communication 203, 69 (2005).J. Minár, H. Ebert, C. De Nadai, N. B. Brookes, F. Venturini,G. Ghiringhelli, L. Chioncel, M. I. Katsnelson, A. I. Lichtenstein.Experimental Observation and Theoretical Description of thePure Fano Effect in the valence-Band Photoemission of Ferromagnets.Physical Review Letters 95, 166401 (2005).G. Monaco, L. Crapanzano, R. Bellissent, W. Crichton,D. Fioretto, M. Mezouar, F. Scarponi, R. Verbeni.Rubberlike dynamics in sulphur above the lambda-transition temperature.Physical Review Letters 95, 255502 (2005).A. J. Moreno, S. V. Buldyrev, E. La Nave, I. Saika-Voivod,F. Sciortino, P. Tartaglia, E. Zaccarelli.Energy landscape of a simple model for strong liquids.Physical Review Letters 95, 157801 (2005).A. J. Moreno, S. H. Chong, W. Kob, F. Sciortino.Dynamical arrest in a liquid of symmetric dumbells.Reorientational hopping for small molecular elongationsJournal of Chemical Physics 123, 204505 (2005).R. Narizzano, V. Erokhin, C. Nicolini.A heterostructure composed of conjugated polymer and copper sulfide nanoparticles.Journal of Physical Chemistry B 109, 15798 (2005).K. Ngai, R. Casalini, S. Capaccioli, M. Paluch, C. M. Paluch.Do theories of the glass transitino in which the structural relaxation timedoes not define the dispersion of the structural relaxation, need revision?Journal of Physical Chemistry B 109, 17356 (2005).SOFT Scientific Report 2004-06126

W. Nosel, T. Gili, S. Capuani, B. Maraviglia.Dipolar field effect described by boson operators techniques:case of intermolecular multiple quantum coherences in liquids.Chemical Physics Letters 406, 452 (2005).K. A. O'Donnell, R. Torre.Characterization of the second-harmonic response of a silver-air interface.New Journal of Physics 7, 154 (2005).A. Paciaroni, S. Ginelli, E. Cornicchi, A. De Francesco, G. Onori.Fast fluctuations in protein powders : the role of hydration.Chemical Physics Letters 410, 400 (2005).M. Paluch, S. Pawlus, S. Hensel-Bielowka, E. Kaminska,D. Prevosto, S. Capaccioli, P. Rolla, K. L. Ngai.Two secondary modes in decahydroisoquinoline:which one is the true Johari-Goldstein process?Journal of Chemical Physics 122, 234506 (2005).I. Pirazzoli, M. Alesiani, S. Capuani, B. Maraviglia, R. Giorni, F. Ridi, P. Baglioni.The influence of superplasticizers on the first stepsof tricalcium silicate hydration studied by NMR techniques.Magnetic Resonance Imaging 23, 277 (2005).E. Pontecorvo, M. Krisch, A. Cunsolo, G. Monaco, A.Mermet, R. Verbeni, F. Sette, G. Ruocco.High frequency longitudinal and transverse dynamics in water.Physical Review E 71, 011501 (2005).P. H. Poole, I. Saika-Voivod, F. Sciortino.Density minimum and liquid-liquid phase transition.Journal of Physics: Condensed Matter 17, L431 (2005).D. Prevosto, S. Capaccioli, M. Lucchesi, P. Rolla.Effect of temperature ad volume on structural relaxation time:interpretation in terms of decrease of configurational entropy.Journal of Non-Crystalline Solids 351, 2611 (2005).D. Prevosto, S. Capaccioli, M. Lucchesi, P. Rolla, R. Casalini.Reply to Comment on “Correlation between configurationalentropy and structural relaxation time in glass-forming liquids”.Physical Review B 71, 136202 (2005).D. Prevosto, S. Capaccioli, M. Lucchesi, P. A. Rolla, M. Paluch, S. Pavlus, I. Ziolo.Emergence of a new features in the high-pressurehigh-temperaturesrelaxation spectrum of tri-propylene glycolJournal of Chemical Physics 122, 061102 (2005).A. M. Puertas, E. Zaccarelli, F. Sciortino.Viscoelastic properties of attractive and repulsive colloidal glasses.Journal of Physics: Condensed Matter 17, L271 (2005).A. Ranfagni, P. Fabeni, G. P. Pazzi, D. Mugnai, A. Agresti, G. Viliani, R. Ruggeri.Relaxation dynamics in the excited state of impurity centers in alkali halides.Physical Review B72, 012101 (2005).127SOFT Scientific Report 2004-06

DisseminationB. Rossi, G. Viliani, E. Duval, L. Angelani, W. Garber.Temperature-dependent vibrational heterogeneities in harmonic glasses.Europhysics Letters 71, 256 (2005).C. Rossi, S. Capuani, F. Fasano, M. Alesiani, B. Maraviglia.DT I of trabecular bone marrow.Magnetic Resonance Imaging 23, 245 (2005).I. Saika-Voivod, F. Sciortino, T. Grande, P. H. Poole.Phase diagram of silica from computer simulation.Physical Review E 70, 061507 (2005).F. Sciortino.Liquid-liquid transitions in one component systems.Journal of Physics: Condensed Matter 17, 32 (2005).F. Sciortino.Potential energy landscape description of supercooled liquids and glasses.Journal of Statistical Mechanics 05015 (2005).F. Sciortino, S. V. Buldyrev, C. De Michele, G. Foffi, N. Ghofraniha, E. La Nave,A. J. Moreno, S. Mossa, I. Saika-Voivod, P. Tartaglia, E. Zaccarelli.Routes to colloidal gel formation.Computational Physics Communication 169, 167 (2005).F. Sciortino, P. Tartaglia.Glassy colloidal systems.Advances in Physics 54, 471 (2005).F. Sciortino, P. Tartaglia, E. Zaccarelli.One dimensional cluster growth and branching gels in colloidal systemwith short-range depletion attraction and screened electrostatic repulsion.Journal of Physical Chemistry B 109, 21942 (2005).T. Scopigno, R. Di Leonardo, L. Comez, A. Q. Baron, D. Fioretto, G. Ruocco.Hard-sphere-like dynamics in a non-hard-spheres-liquid.Physical Review Letters 94, 155301 (2005).T. Scopigno, R. Di Leonardo, L. Comez, A. Q. Baron, D. Fioretto, G. Ruocco, W. Montfrooij.Reply to the Comment on "Hard sphere-like dynamics in a non hard sphere liquid".Physical Review Letters 95, 269602 (2005).T. Scopigno, G. Ruocco, F. Sette.Microscopic dynamics in liquid metals: the experimental point of view.Review of Modern Physics 77, 881 (2005).M. Sega, R. Vallauri, S. Melchionna.Diffusion of water in confined geometry: the case of a multilamellar bilayer.Physical Review E 72, 041201 (2005).S. Sennato, F. Bordi, C. Cametti, C. Coluzza, A. Desideri, S. Rufini.Evidence of domain formation in cardiolipin-glycerophospholipidmixed monolayers: a thermodynamic and AFM study.Journal of Physical Chemistry B 109, 15950 (2005).SOFT Scientific Report 2004-06128

S. Sennato, F. Bordi, C. Cametti, A. Di Biasio, M. Diociaiuti.Polyelectrolyte-liposome complexes: an equilibriumcluster phase close to the isoelectric condition.Colloids and Surfaces A 270, 138 (2005).S. Sennato, F. Bordi, C. Cametti, M. Dociaiuti, P. Malaspina.Charge patch attraction and reentrant condensation in DNA-liposome complexes.Biochimica and Biophysica Acta 1714, 11 (2005).S. Suga, A. Sekiyama, S. Imada, A. Shigemoto, A. Yamasaki, M. Tsunekawa,C. Dallera, L. Braicovich, T. L. Lee, O. Sakai, T. Ebihara, Y. Onuki.Kondo lattice effects of YbAl3 suggested by temperaturedependence of High Accuracy High Energy Photoelectron Spectroscopy.Journal of Physical Society of Japan 74, 2880 (2005).L. Tassini, F. Gorelli, L. Ulivi.High temperatures structures and orientational disordered in compressed solid nitrogen.Journal of Chemical Physics 122, 074701 (2005).M. Tehei, G. Zaccai.Adaptation to estreme environments: macromolecules dynamics in complex systems.Biochimica and Biophysica Acta 1724, 404 (2005).L. Xu, P. Kumar, S. V. Buldyrev, S. H. Chen, P. H. Poole, F. Sciortino, H. E. Stanley.Relation between the Widom line and dynamic crossoverin systems with a liquid-liquid phase transition.Proceedings of the National Accademy of Science 102, 16558 (2005).A. Yamasaki, S. Imada, A. Sekiyama, M. Tsunekawa, T. Nanba, C. Dallera, L. Braicovich,T.Lee, H. Sugawara, H. Sato, C. Sekin, I. Shirotani, R. Settai, Y. Onuki, H. Harima, S. Suga.Bulk-sensitive photoemission spectroscopy of Pr-based filled skutterudites.Journal of Electron Spectroscopy and Related Phenomena 144-147, 621 (2005).A. Yamasaki, A. Sekiyama, M. Tsunekawa, S. Imada,A. Ochiai, C. Dallera, L. Braicovich, T.-L. Lee, S. Suga.Hard and soft X-ray photoemission spectroscopies of ferromagnetic Sm 4 As 3 .Journal of Electron Spectroscopy and Related Phenomena 144-147, 617 (2005).A. Yamasaki, S. Imada, A. Sekiyama, M. Tsunekawa, C. Dallera,L. Braicovich, T.-L. Lee, H. Sugawara, H. Sato, R. Settai, Y. Ônuki, S. Suga.Bulk-sensitive photoemission spectroscopy for heavy fermion Pr compounds using X-rays.Journal of the Physical Society of Japan 74, 2045 (2005).A. Yamasaki, A. Sekiyama, M. Tsunekawa, S. Imada,S. Suga, C. Dallera, L. Braicovich, T.-L. Lee, A. Ochiai.Photoemission spectroscopy of Sm 4 As 3 using soft and hard x-rays.Journal of the Physical Society of Japan 74, 2538 (2005).E. Zaccarelli, S.V. Buldyrev, E. La Nave, A.J. Moreno,I. Saika-Voivod , F. Sciortino, P. Tartaglia.Model for reversible colloidal gelation.Physical Review Letters 94, 218301 (2005).129SOFT Scientific Report 2004-06

DisseminationE. Zaccarelli, C. Mayer, A. Asteriadi, C. N. Likos, F. Sciortino, J. Roovers,H. Iatrou, N. Hadjichristidis, P. Tartaglia, H. Lowen, D. Vlassopoulos.Tailoring the flow of soft glasses by soft additives.Physical Review Letters 95, 268301 (2005).F. Zamponi, F. Bonetto, L. Cugliandolo, J. Kurchan.A fluctuation theorem for non-equlibrium relaxational systems driver by external forces.Journal of Statistical Mechanics-Theory and Experiments P09013 (2005).F. Zamponi, G. Ruocco, L. Angelani.Generalized fluctuation relation and effective temperature in a driven fluctuation.Physical Review E 71, 020101 (2005).Z. Zhao, P. Mani, G. J. Mankey, G. Gubbiotti, S. Tacchi,F. Spizzo, W. T. Lee, C. T. Yu, M. J. Pechan.Magnetic properties of uniaxial synthetic antiferromagnets for spin-valve applications.Physical Review B 71, 104417 (2005).2006L. Angelani, C. Conti, G. Ruocco, F. Zamponi.Glassy behaviour of light.Physical Review Letters 96, 065702 (2006).L. Angelani, C. Conti, G. Ruocco, F. Zamponi.Glassy behaviour of light in random lasers.Physical Review B 74, 104207 (2006).R. Angelini, T. Scopigno, M. Krisch, G. Ruocco.High frequency dynamics of orientationally disordered molecular crystal.Journal of Non-Crystalline Solids 352, 4552 (2006).E. Annese, A. Barla, C. Dallera, G. Lapertot, J. P. Sanchez, G. Vankó.The complete divalent-to-trivalent transition of Sm in SmS:implications for the high-pressure magnetically ordered state.Physical Review B 73, 140409(R) (2006).C. Aruta, G. Ghiringhelli, A. Tebano, N. G. Boggio,N. B. Brookes, P. G. Medaglia, G. Balestrino.Strain induced x-ray absorption linear dichroism in La 0.7 Sr 0.3 MnO 3 thin films.Physical Review B 73, 235121 (2006).U. Bafile, E. Guarini, F. Barocchi.Collective acoustic modes as renormalized damped oscillators:unified description of neutron and x-ray scattering data from classical fluids.Physical Review E 73, 06123 (2006).C. Baldacchini, C. Mariani, M. G. Betti.Adsorption of pentacene on filled d-band metal surfaces:Long-range ordering and adsorption energy.Journal of Chemical Physics 124, 154702 (2006).SOFT Scientific Report 2004-06130

F. Bencivenga, A. Cunsolo, M. Krisch, G. Monaco, G. Ruocco, F. Sette.Adiabatic and isothermal sound waves: the case of supercritical nitrogen.Europhysics Letters 75, 70 (2006).V. Bercu, M. Martinelli, C. A. Massa, L. A. Pardi, D. Leporini.Signatures of the fast dynamics in glassy polystyrene by multi-frequency,high-field Electron Paramagnetic Resonance of molecular guests.Journal of Non-Crystalline Solids 352, 5029 (2006).R. Berlasso, C. Dallera, F. Borgatti, C. Vozzi, G. Sansone, S. Stagira, M. Nisoli, G.Ghiringhelli, P. Villoresi, L. Poletto, M. Pascolini, S. Nannarone, S. De Silvestri, L. Braicovich.High-order laser harmonics and synchrotron study of transition metals M 2,3 edges.Physical Review B 73, 115101 (2006).P. Bertoncello, A. Notargiacomo, V. Erokhin, C. NicoliniFunctionalization and photoelectrochemical characterization of poly 33’ vinylcarbazolemulty-walled carbon nanotube (PVK-MWNT) Langmuir-Schaefer films.Nanotechnology 17, 699 (2006).E. Bianchi, J. Largo, P. Tartaglia, E. Zaccarelli, F. Sciortino.Phase diagram of patchy colloids: Towards empty liquids.Physical Review Letters 97, 168301 (2006).F. Bonetto, G. Gallavotti, A. Giuliani, F. Zamponi.Chaotic hypothesis, fluctuation theorem and singularities.Journal of Statistical Physics 123, 39 (2006).A. Bonincontro, C. Cametti, B. Nardiello, S. Marchetti, G. Onori.Dielectric behavior of DNA in water-organic co-solvent mixtures.Biophysical Chemistry 121, 7 (2006).A. Bonincontro, E. Spigone, M. R. Pena, C. Letizia, C. La Mesa.Lysozyme binding onto cat-anionic vesicles.Journal of Colloid and Interface Science 304, 342 (2006).F. Bordi, C. Cametti, C. Marianecci, B. Paoli, S. Sennato.Charge renormalization in planar and spherical charged lipid aqueous interfaces.Journal of Physical Chemistry B 110, 4808 (2006).F.Bordi, C. Cametti, M. Diociaiuti, S.Sennato.Dynamically entrapped phase in polyelectrolyte-charged liposomecomplexes: direct evidence of multi-compartment aggregates.Biophysical Journal 91, 1513 (2006).F. Bordi, C. Cametti, S. Sennato, D. Viscomi.Counterion release in overcharging of polyion-liposome complexes.Physical Review E 74, 030402(R) (2006).F. Bordi, C. Cametti, S. Sennato, D. Viscomi.Conductometric evidence for intact polyion-induced liposome clusters.Journal of Colloid and Interface Science 304, 512 (2006).F. Bordi, C. Cametti, S. Sennato, S. Zuzzi, S. Dou, R. H. Colby.Dielectric scaling in polyelectrolyte solutions with different solvent quality.Physical Chemistry Chemical Physics 8, 3653 (2006).131SOFT Scientific Report 2004-06

DisseminationV. Bortolotti, M. Camaiti, C. Casieri, F. De Luca, P. Fantazzini, C. Terenzi.Water absorption kinetics in different wettability conditions studied at pore and samplescale in porous media by portable singlesided and laboratory imaging devices.Journal of Magnetic Resonance 181, 287(2006).E. Brunello, P. Bianco, G. Piazzesi, M. Linari, M. Reconditi,P. Panine, T. Narayanan, W. Helsby, M. Irving, V. Lombardi.Structural changes in the myosin filament and cros-bridges during active force developmentin single intact frog muscle fibres: stiffness and X-ray diffraction measurements.Journal of Physiology 577, 971 (2006).V. Calandrini, A. Deriu, G. Onori, A. Paciaroni, M. T. F. Telling.Pressure effect on water dynamics in tert-butyl alcohol/water solutions.Journal of Physics: Condensed Matter 18, S2363 (2006).M. Cammarata, M. Lorenc, T. K. Ki, J. H. Lee, Q. Y. Kong,E. Pontecorvo, M. Lo Russo, G. Schiro’, A. Cupane, M. Wulff, H. Ihee.Impulsive solvent heating probed by picosecond x-ray diffraction.Journal of Chemical Physics 124, 124504 (2006).P. Camorani, M. P. Fontana.Optical control of structural morphology in azobenzene containing polymeric liquid crystals.Physical Review E 73, 011703 (2006).S. Capaccioli, K. Kessairi, D. Prevosto, M. Lucchesi, K. L. Ngai.Genuine Johari-Goldstein beta-relaxations in glass-forming binary mixtures.Journal of Non-Crystalline Solids 352, 4643–4648 (2006)F. Carace, P. Vavassori, G. Gubbiotti, S. Tacchi, M. Madami, G. Carlotti, T. Okuno.Magnetization reversal process in elliptical Permalloy nanodots.Thin Solid Films 515, 727 (2006).S. Caponi, A. Fontana, E. Fabiani, M. A. González, L. Borjesson, A. Matic, C. Armellini.The Debye-Waller factor approaching the glass-transition temperature in phosphate glasses.Journal of Non-Crystalline Solids 352 4577 (2006).G. Carlotti, G. C. Gazzadi, G. Gubbiotti, M. Madami, S. Tacchi, P. Valvassori.Intrinsic magnetic anisotropy versus coupling in arrays of closelyspaced circular Fe/GaAs(110) dots, patterned by focused ion beam.Thin Solid Films 515, 739 (2006).R. Casalini, S. Capaccioli, C. M. Roland.What can we learn by squeezing a liquid?Journal of Physical Chemistry B 110, 11491 (2006).M. Chinappi, E. De Angelis, S. Melchionna, C. M. Casciola, S. Succi, R. Piva.Molecular dynamics simulation of ratchet motion in an asymmetric nanochannel.Physical Review Letters 97, 144509 (2006).K. Y. Choi, V. P. Gnezdilov, P. Lemmens, L. Capogna,M. R. Johnson, M. Sofin, A. Maljuk, M. Jansen, B. Keimer.Magnetic excitations and phonons in the spin-chain compound NaCu 2 O 2 .Physical Review B 73, 094409 (2006).SOFT Scientific Report 2004-06132

R. Cignini, R. Melzi, F. Tedoldi, C. Casieri, F. De Luca.Large surface mapping by unilateral NMR scanner.Magetic Resonance Imaging 24, 813 (2006).L. Comez, S. Corezzi, G. Monaco, R. Verbeni, D. Fioretto.Non-ergodicity in a locally ordered fragile glass former.Journal of Non-Crystalline Solids 352, 4531 (2006).C. Conti, N. Ghofraniha, G. Ruocco, S. Trillo.Laser beam filamentation in fractal aggregates.Physical Review Letters 97, 123903 (2006).C. Conti, M. Peccianti, G. Assanto.Complex dynamics and configurational entropy of spatial optical solitons in non-local media.Optics Letters 31, 2030 (2006).S. Corezzi, L. Comez, G. Monaco, R. Verbeni, D. Fioretto.Bond-induced ergodicity breakdown in reactive mixtures.Physical Review Letters 96, 255702 (2006).S. Corezzi, D. Fioretto, P. Rolla.Comment on "Decrease in the configurational entropy during a melt's polymerization".Chemical Physics 323, 622 (2006)E. Cornicchi, M. Marconi, G. Onori, A. Paciaroni.Controlling the protein dynamical transition with sugar-basedbioprotectant matrices: A neutron scattering study.Biophysical Journal 91, 289 (2006).S. Cozzolino, L. Galantini, E. Giglio, S. Hofmann, C. Leggio, N. V. Pavel.Structure of sodium glycodeoxycholate micellar aggregatesfrom small-angle X-ray scattering and light-scattering techniques.Journal of Physical Chemistry B 110, 12351 (2006).A. Cunsolo, A. Orecchini, C. Petrillo, F. Sacchetti.Quasielastic neutron scattering investigation of thepressure dependence of molecular motions in liquid water.Journal of Chemical Physics 124, 084503 (2006).C. Dallera, O. Wessely, M. Colarieti-Tosti, O. Eriksson, R. Ahuja, B. Johansson,M.I. Katsnelson, E. Annese, J.-P. Rueff, G. Vankó, L. Braicovich, M. Grioni.Understanding of mixed valence materials: Effects of dynamicalcore-hole screening in high pressure x-ray spectroscopy.Physical Review B 74, 081101(R) (2006).G. D'Arrigo, G. Briganti, M. Maccarini.Shear and longitudinal viscosity of nonionic aqueous solutions.Journal of Physical Chemistry B 110, 4612 (2006).C. De Michele, S. Gabrielli, P. Tartaglia, F. Sciortino.Dynamics in the presence of attractive patchy interactions.Journal of Physical Chemistry B 110, 8064 (2006).133SOFT Scientific Report 2004-06

DisseminationC. De Michele, A. Scala, R. Schilling.Molecular correlation functions for uniaxial ellipsoids in the isotropic state.Journal of Chemical Physics 124, 104509 (2006).C. De Michele, P. Tartaglia, F. Sciortino.Slow dynamics in a primitive tetrahedral network model.Journal of Chemical Physics 125, 0000 (2006).A. Di Cicco, A. Trapananti, E. Principi, S. De Panfilis, A. Filipponi.Polymorphism and metastable phenomena in liquid tin under pressure.Applied Physics Letters 89, 221912 (2006).A. Di Falco, C. Conti, G. Assanto.Impedance matching in photonic crystal microcavities for second-harmonic generation.Optics Letters 31, 250 (2006).A. Di Falco, C. Conti, G. Assanto.Quadratic phase matching in slot waveguides.Optics Letters 31, 3146 (2006).R. Di Leonardo, S. Gentilini, F. Ianni, G. Ruocco.Aging and flow in a complex fluid.Journal of Non-Crystalline Solids 352, 4928 (2006).R. Di Leonardo, J. Leach, H. Mushfique, J. M. Cooper, G. Ruocco, M. J. Padgett.Multi-point holographic optical micro-velocimetry.Physical Review Letters 96, 134502 (2006).A. Di Michele, M. Freda, G. Onori, M. Paolantoni, A. Santucci, P. Sassi.Modulation of Hydrophobic Effect by Cosolutes.Journal of Physical Chemistry B 110, 21077 (2006).V. Erokhin, T. Berzina, P. Camorani, M. P. Fontana.Conducting polymer-solid electrolyte fibrilar composite material for adaptive networks.Soft Matter 2, 870 (2006).M. Fanetti, L. Gavioli, M. Sancrotti, M. G. Betti.Morphology of pentacene films deposited on Cu(119) vicinal surface.Applied Surface Science 252, 5568 (2006).G. Foffi, F. Sciortino.Extended law of corresponding states in short-range square wells:A potential energy landscape study.Physical Review E 74, 050401 (2006).A. Fontana, L. Orsingher, F. Rossi, U. Buchenau.Dynamics of a hydrogenated silica xerogel: A neutron scattering study.Physical Review B 74, 172304 (2006).G. Garreffa, S. Ken, M. A. Macri’, G. Giulietti, F. Giove, C. Colonnese,E. Venditti, E. De Cesare, V. Galasso, B. Maraviglia.BOLD signal and vessel dynamics: a hierarchical cluster analysis.Magnetic Resonance Imaging 24, 411 (2006).SOFT Scientific Report 2004-06134

G. Ghiringhelli, M. Matsubara, C. Dallera, F. Fracassi,A. Tagliaferri, N. B. Brookes, A. Kotani, L. Braicovich.Resonant inelastic x-ray scattering of MnO: L2,3 edgemeasurements and assessment of their interpretation.Physical Review B 73, 035111 (2006).V. M. Giordano, F. A. Gorelli, R. Bini.Infrared study of high-pressure molecular phases of carbon dioxide.Journal of Low Tempearture Physics 32, 1067 (2006).A. Giugni, A. Cunsolo.Structural relaxation in the dynamics of glycerol:a joint visible, UV and x-ray inelastic scattering study.Journal of Physics: Condensed Matter 18, 889 (2006).K. Grzybowska, A. Grzybowski, J. Ziolo, M. Paluch, S. Capaccioli.Dielectric secondary relaxations in polypropylene glycols.Journal of Chemical Physics 125, 044904 (2006).F. Gorelli, M. Santoro, T. Scopigno, M. Krisch, G. Ruocco.Liquid-like behavior of supercritical fluids.Physical Review Letters 97, 245702 (2006).G. Gubbiotti, G. Carlotti, T. Ono, Y. Roussigne.High frequency magnetic excitations in patterned NiFe/Cu/NiFetrilayered stripes subjected to a transverse magnetic field.Journal of Applied Physics 100, 023906 (2006).G. Gubbiotti, M. Madami, S. Tacchi, G. Carlotti, T. Okuno.Normal mode splitting in interacting arrays of cylindrical permalloy dots.Journal of Applied Physics 99, 08C701 (2006).G. Gubbiotti, M. Madami, S. Tacchi, G. Carlotti, T. Okuno.Field dependence of spin excitations in NiFe/Cu/NiFe trilayered circular dots.Physical Review B 73, 144430 (2006).G. Gubbiotti, M. Madami, S. Tacchi, G. Carlotti,H. Tanigawa, T. Ono, L. Giovannini, F. Montoncello, F. Nizzoli.Splitting of spin excitations in nanometric rings induced by a magnetic field.Physical Review Letters 97, 247203 (2006).G. Gubbiotti, M. Madami, S. Tacchi, G. Socino, G. Carlotti, T. Okuno.Effect of interdot dipolar coupling on the magnetic properties of permalloy nano-cylinders.Surface Science 600, 4143 (2006).J. Gutierrez, F. J. Bermejo, J. M. Barandiaran, S. P. Cottrell,P. Romano, C. Mondelli, L. Fernandez-Barquin, A. Pena.The role of disorder in Fe-doped CMR manganites as explored by µSR spectroscopy.Physica B 374, 63 (2006).J. Gutierrez, F. J. Bermejo, J. M. Barandiaran, S. P. Cottrell,P. Romano, C. Mondelli, J.R. Stewart, L. Fernandez-Barquin, A. Pena.Role of disorder and competing ferromagnetic and antiferromagnetic interactionsin the magnetic, electrical, and dynamic properties of La 0.7 Pb 0.3 (Mn 1-x Fe x )O 3Physical Review B 73, 054433 (2006).135SOFT Scientific Report 2004-06

DisseminationJ. Gutierrez, F. J. Bermejo, N. Veglio, J. M. Barandiaran, P. Romano,C. Mondelli, M. A. Gonzalez, A. P. Murani.Structural correlations in La 0.7 Pb 0.3 (Mn 1−x Fe x )O 3 manganitesas probed by small-angle and polarized neutron diffraction.Journal of Physics: Condensed Matter 18, 9951 (2006).F. Ianni, D. Lasne, R. Sarcia, P. Hebraud.Relaxation of jammed colloidal suspensions after shear cessation.Physical Review E 74, 011401 (2006).M. Iannuzzi, A. Orecchini, F. Sacchetti, P. Facchi, S. Pascazio.Direct experimental evidence of free-fermion antibunching.Physical Review Letters 96, 080402 (2006).A. Kanjilal, F. Bussolotti, F. Crispoldi, M. Beccari, V. Di Castro, M. G. Betti, C. Mariani.Growth of long range ordered pentacene/benzenethiol/Cu(100) heterostructure.Journal de Physique IV 132, 301(2006).L. Larini, A. Barbieri, D. Leporini.Transient and equilibrated single-molecule crystals of polyethylene:Molecular-dynamics studies of the lamellar fold length?Physica A 364, 183 (2006).L. Larini, D. Leporini.Free-energy effects in single-molecule polymer crystals.Journal of Non-Crystalline Solids 352, 5021 (2006).J. Leach, H. Mushfique, R. Di Leonardo, M. Padgett, J. Cooper.An optically driven pump for microfluidics.Lab on a Chip 6, 735 (2006).M. Lucchesi, A. Dominjon, S. Capaccioli, D. Prevosto, P. A. Rolla.Polarization Fluctuations near the Glass Transition.Journal of Non-Crystalline Solids 352, 4920–4927 (2006).M. A. Macri’, C. Colonnese, G. Garreffa, F. Fattapposta,R. Restuccia, F. Bianco, L. La Bruna, B. Maraviglia.A Chemical Shift Imaging study on regional metabolite distribution in a CADASIL family.Magnetic Resonance Imaging 24, 443 (2006).M. A. Macri’, N. D'Alessandro, C. Di Giulio, P. Di Iorio,S. Di Luzio, P. Giuliani, G. Bianchi, E. Esposito.Regional changes in the metabolite profile following long-term hypoxiaischemiain the brain of young and aged rats: a quantitative proton MRS study.Neurobiological Aging 27, 98 (2006).M. A. Macri’, G. Garreffa, F. Giove, M. Moraschi,G. Giulietti, N. Modugno, C. Colonnese, B. Maraviglia.A cluster-based quantitative procedure in an fMRI study of Parkinson disease.Magnetic Resonance Imaging 24, 419 (2006).SOFT Scientific Report 2004-06136

M. Madami, S. Tacchi, G. Carlotti, G. Gubbiotti, G. Socino.Thickness dependence of magnetic anisotropy in uncovered and Cu-coveredFe/GaAs(110) ultrathin films studied by in situ Brillouin light scatteringJpurnal of Applied Physics 99, 08J701 (2006).S. Marchetti, G. Onori, C. Cametti.Calorimetric and dynamic light-scattering investigation of surfactant-DNA complexes.Journal of Physical Chemistry B 110, 24761 (2006).A. Martinelli, M. Ferretti, C. Castellano, C. Mondelli, M. R. Cimberle, M. Tropeano, C. Ritter.Effect of Cr substitution on the crystal and magnetic structureof (Pr 0.55 Ca 0.45 )MnO 3 : A neutron powder diffraction investigation.Physical Review B 73, 064423 (2006).A. Martinelli, M. Ferretti, C. Castellano, M. R. Cimberle, M. Tropeano, C. Mondelli.Effect of Cr substitution on the crystal and magnetic structure of (Pr 0.55 Ca 0.45 )MnO 3 .Advances in Science and Technology 52, 93 (2006).C. Masciovecchio, G. Baldi, S. Caponi, L. Comez, S. Di Fonzo, D. Fioretto,A. Fontana, A. Gessini, S. C. Santucci, F. Sette, G. Viliani, P. Vilmercati, G. Ruocco.Evidence for a crossover in the frequency dependence of the acoustic attenuation in v-SiO 2 .Physical Review Letters 97, 035501 (2006).M. Medarde, C. Dallera, M. Grioni, J. Voigt, E. Pomjakushina,K. Conder, Th. Neisius, O. Tjernberg, S. N. Barilo.The low-temperature spin-state transition LaCoO 3 investigatedby resonant x-ray absorption at the Co K edge.Physical Review B 73, 054424 (2006).S. Melchionna.Numerical integration of projective Hamiltonian dynamics.Molecular Physics 104, 3045 (2006).S. Melchionna, R. Sinibaldi, G. Briganti.Explanation of the stability of thermophilic proteins based on unique micromorphologyBiophysical Journal 90, 4204 (2006).S. Melchionna, S. Succi, J. P. Hansen.Simulation of single-file ion transport with the lattice Fokker-Planck equation.Physical Review E 73, 017701 (2006).M. Missori, C. Mondelli, M. de Spirito, C. Castellano, M. Bicchieri,R. Schweins, G. Arcovito, M. Papi, A. Congiu Castellano.Modifications of the mesoscopic structure of cellulose in paper degradation.Physical Review Letters 97, 238001 (2006).D. Molin, A. Barbieri, D. Leporini.Accurate excluded-volume corrections to the single-chainstatic properties of a melt of unentangled polymers?Journal of Physics: Condensed Matter 18, 7543 (2006).A. Monaco, A. I. Chumakov, G. Monaco, W. A. Crichton,A. Meyer, L. Comez, D. Fioretto, J. Korecki, R. Rüffer.Effect of densification on the Density of Vibrational States of Glasses.Physical Review Letters 97, 135501 (2006).137SOFT Scientific Report 2004-06

DisseminationA. Monaco, A. I. Chumakov, Y. Z. Yue, G. Monaco, L. Comez, D. Fioretto, W. Crichton, R. Ruffer.Density of vibrational states of a hyperquenched glass.Physical Review Letters 96, 205502 (2006).M. Monni, C. Ferdeghini, M. Putti, P. Manfrinetti, A. Palenzona, M. Affronte,P. Postorino, M. Lavagnini, A. Sacchetti, D. Di Castro, F. Sacchetti, C. Petrillo, A. Orecchini.Role of charge doping and lattice distortions in codoped Mg 1-x (AlLi) x B 2 compoundsPhysical Review B 73, 214508 (2006).A. J. Moreno, I. Saika-Voivod, E. Zaccarelli,E. La Nave, S. V. Buldyrev, P. Tartaglia, F. Sciortino.Non-Gaussian energy landscape of a simple model for strong networkformingliquids: Accurate evaluation of the configurational entropy.Journal of Chemical Physics 124, 204506 (2006).D. Moroni, J. P. Hansen, S. Melchionna S. Succi.On the use of lattice Fokker-Planck models for hydrodynamics.Europhysics Letters 75, 399 (2006).D. Moroni, B. Rotenberg, J. P. Hansen, S. Melchionna, S. Succi.Solving the Fokker-Planck kinetic equation on a lattice.Physical Review E 73, 066707 (2006).R. Muzzalupo, G. Gente, C. La Mesa, E. Caponetti,D. Chillura-Martino, L. Pedone, M. L. Saladino.Micelles in mixtures of sodium dodecyl sulfate and a bolaform surfactant.Langmuir 22, 6001 (2006).I. Neudecker, G. Woltersdorf, B. Heinrich, T. Okuno, G. Gubbiotti , C. H. Back.Comparison of frequency,field, and time domain ferromagnetic resonance methods.Journal of Magnetism and Magnetic Materials 307, 148 (2006).K. L. Ngai, S. Capaccioli, C. M. Roland.Comment on “A Molecular Dynamics Simulation Study of Relaxation Processes in theDynamical Fast Component of Miscible Polymer Blends” by D. Bedrov and G.D. Smith.Macromolecules, 00, 8543 (2006).A. Orecchini, F. Sacchetti, C. Petrillo, P. Postorino,A. Congeduti, Ch. Giorgetti, F. Baudelet, G. Mazzone.Magnetic states of iron in metastable fcc Fe-Cu alloys.Journal of Alloys Compound 424, 27 (2006).B. Orioni, M. Roversi, C. La Mesa, F. Asaro, G. Pellizer, G. D'Errico.Polymorphic Behavior in Protein-Surfactant Mixtures:The Water-Bovine Serum Albumin-Sodium Taurodeoxycholate System.Journal of Physical Chemistry B 110, 12129 (2006).M. G. Ortore, F. Spinozzi, F. Carsughi, P. Mariani, M. Sonetti, G. Onori.High pressure small-angle neutron scattering study of the aggregationstate of beta-lactoglobulin in water and in water/ethylene-glycol solutions.Chemical Physics Letters 418, 342 (2006).SOFT Scientific Report 2004-06138

A. Paciaroni, E. Cornicchi, A. De Francesco, M. Marconi, G. Onori.Conditioning action of the environment on the proteindynamics studied through elastic neutron scattering.European Biophysical Journal 35, 591 (2006).A. Paciaroni, M. Casciola, E. Cornicchi, M. Marconi,G. Onori, M. Pica, R. Narducci, A. De Francesco, A. Orecchini.Dynamics of water confined in fuel cell Nafion membranescontaining zirconium phosphate nanofiller.Journal of Physics: Condensed Matter 18, S2029 (2006).A. Paciaroni, M. Casciola, E. Cornicchi, M. Marconi, G. Onori, M. Pica, R. Narducci.Temperature-dependent dynamics of water confined in Nafion membranes.Journal of Physical Chemistry B 110, 13769 (2006).G. Parisi, F. Zamponi.The ideal glass transition of Hard Spheres.Journal of Chemical Physics 123, 144501 (2005).C. Petrillo, F. Sacchetti, A. Orecchini, R. De Renzi, M. Ricco’.Electron-electron correlations in fullerene probed by incoherent scattering of x rays.Physical Review B 74, 085404 (2006).C. Pierleoni, C. Addison, J. P. Hansen, V. Krakoviack.Multi-scale coarse-graining of diblock copolymer self-assembly:from monomers to ordered micelles.Physical Review Letters 96, 128302 (2006).M. Plazanet, M. Dean, M. Merlini, A. Huller, H. Emerich,C. Meneghini, M. R. Johnson, H. P. Trommsdorff.Crystallization on heating and complex phase behavior of alpha-cyclodextrin solutions.Journal of Chemical Physics 125, 154504 (2006).P. Porcari. S. Capuani. R. Campanella. A. La Bella, L. M. Migneco. B. Maraviglia.Multi-nuclear MRS and 19 F MRI of 19 F-labelled and 10 B-enriched p-boronophenylalaninefructosecomplex to optimize boron neutron capture therapy.Physical Medics Biology 51, 3141 (2006).D. Prevosto, S. Capaccioli, M. Lucchesi, P.A. Rolla, M. Paluch, S. Pawlus.Effect of the thermodynamic history of the glassy stateon secondary relaxation in phenolphthalein-dimethyl-ether.Physical Review B 73, 104205 (p.5) (2006).D. Prevosto, S. Capaccioli, P.A. Rolla, M. Paluch,S. Pawlus, S. Hensel-Bielowka, E. Kaminska.Secondary dielectric relaxation in Decahydroisoquinoline-Cyclohexane mixture.Journal of Non-Crystalline Solids 352, 4685–4689 (2006).A. Ranfagni, P. Fabeni, G. P. Pazzi, A. Agresti, G. Viliani, R. Ruggeri.Relaxation dynamics, dissipative tunneling, solitons, and anomalous decay.Physical Review B 74, 195107 (2006).139SOFT Scientific Report 2004-06

DisseminationM. Reale, M. A. De Lutiis, A. Patruno, L. Speranza, M. Felaco,A. Grilli, M. A. Macri’, S. Comani, P. Conti, S. Di Luzio.Modulation of MCP-1 and iNOS by 50-Hz sinusoidal electromagnetic field.Nitric Oxide-Biology and Chemistry 15, 50 (2006).B. Rossi, P. Verrocchio, G. Viliani.Vibrational properties of inclusion complexes: The case of indomethacin-cyclodextrin.Journal of Chemical Physics 125, 044511 (2006).B. Ruzicka, L. Zulian, and G. Ruocco.More on phase diagram of Laponite.Langmuir 22, 1106 (2006).J. Sabín, G. Prieto, S. Sennato, J. M. Ruso, R. Angelini, F. Bordi, F. Sarmento.Effect of Gd 3+ on the colloidal stability of liposomes.Physical Review E 74, 031913 (2006).M. Santoro, F. A. Gorelli.High pressure solid state chemistry of carbon dioxide.Chemical Society Review 35, 918 (2006).M. Santoro, F. A. Gorelli, R. Bini, G. Ruocco, S. Scandolo, W. Crichton.Carbonia: the amorphous silicalike carbon dioxide.Nature 441, 857 (2006).S. C. Santucci, D. Fioretto, L. Comez, A. Gessini, C. Masciovecchio.Is there any fast sound in water?Physical Review Letters 97, 225701 (2006).T. Scopigno, L.-B. Suck, R. Angelini, F. Albergamo, G. Ruocco.High frequency dynamics in metallic glasses.Physical Review Letters 96, 135501 (2006).R. Sinibaldi, C. Casieri, S. Melchionna, G. Onori, A. Segre, S. Viel, L. Mannina, F. De Luca.The role of water coordination in binary mixtures. A study of two modelamphiphilic molecules in aqueous solutions by molecular dynamics and NMR.Journal of Physical Chemistry B 110, 8885 (2006).R. L. Stamps, A. Stollo, M. Madami, S. Tacchi, G. Carlotti, G. Gubbiotti, M. Fabrizioli, J. Fujii.Measurement of spin waves and activation volumesin superparamagnetic Fe films on GaAs(100).Physical Review B 74, 134401 (2006).F. Sterpone, G. Marchetti, C. Pierleoni, M. Marchi.Molecular modeling and simulation of water near model micelles:Diffusion, rotational dynamics and structure of the hydration interface.Journal of Physical Chemistry B 110, 11504 (2006).F. Sterpone, C. Pierleoni, G. Briganti, M. Marchi.Structure and Dynamics of hydrogen bonds in the interface of a C 12 E 6spherical micelle in water solution: A MD study at various temperatures.Journal of Physical Chemistry B 110, 18254 (2006).SOFT Scientific Report 2004-06140

S. Succi, S. Melchionna, J. P. Hansen.Lattice Fokker-Planck equation.International Journal of Modern Physics C 17, 459 (2006).S. Tacchi, A. Stollo, M. Madami, G. Gubbiotti, G. Carlotti, M. G. Pini, P. Politi, R. L. Stamps.Anisotropy effects on the magnetic excitations of epitaxialultrathin films below and above the Curie temperature.Surface Science 600, 4147 (2006).A. Taschin, P. Bartolini, R. Eramo, R. Torre.Supercooled water relaxation dynamics probedwith heterodyne transient grating experiments.Physical Review E 74, 031502 (2006).M. Tehei, J. C. Smith, C. Monk, J. Ollivier, M. Oettl, V. Kurkal, J. L. Finney, R. M. Daniel.Dynamics of immobilized and native Escherichia colidihydrofolate reductase by quasielastic neutron scattering.Biophysical Journal 90, 1090 (2006).V. H. S. Tellini, A. Jover, L. Galantini, N. V. Pavel, F. Meijide, J. V. Tato.New lamellar structure formed by an adamantyl derivative of cholic acid.Journal of Physical Chemistry B 110, 13679 (2006).K. D. Wulff, D. Cole, R. Clark, R. Di Leonardo, J. Leach, J. Cooper, G. Gibson, M. Padgett.Aberration correction in holographic optical tweezers.Optics Express 14, 4169 (2006).S. Yannopoulos, K. S. Andrikopoulos, G. Ruocco.On the analysis of the vibrational Boson peak and low-energy excitations in glasses.Journal of Non-Crystalline Solids 352, 4541 (2006).E. Zaccarelli, I. Saika-Voivod, A.J. Moreno, S.V. Buldyrev, P. Tartaglia, F. Sciortino.Gel to glass transition in simulation of a valence-limited colloidal system.Journal of Chemical Physics 124, 124908 (2006).E. Zaccarelli, I. Saika-Voivod, A. J. Moreno, E. La Nave,S. V. Buldyrev, F. Sciortino, P. Tartaglia.Mode-coupling theory predictions for a limited valency attractive square well model.Journal of Physics: Condensed Matter 18, S2373 (2006).Other PublicationsD. Aisa, E. Babucci, F. Barocchi, A. Cunsolo, F. d’Anca, A. De Francesco, F. Formisano, T.Gahl, E. Guarini, S. Jahn, A. Laloni, H. Mutka, A. Orecchini, C. Petrillo, W.-C. Pilgrim, et al.BRISP-A New Thermal Neutron Brillouin Scattering Spectrometer at the ILL,in Notiziario Neutroni e Luce di Sincrotrone 10, n.1, 20 (2005).F. Bianco, M. Lucchesi, S. Capaccioli, L. Fronzoni, P. Allegroni.Fluctuations in Electrohydrodynamic instability,in AIP Conference Proceedings, November 14, 2005 -Volume 800, pp. 64-69.141SOFT Scientific Report 2004-06

DisseminationF. Bordi, C. Cametti, S. Sennato.Electrical Properties of Aqueous Liposomi Suspensions,in Advances in planar lipid bilayers and liposomes, Vol 4, A. Leitmannova Ed.(2006).F. Bordi, C. Cametti.Biomembranes, in Encyclopedia of Condensed Matter Physics.Eds. G. F. Bassani, G. L. Liedl, P. Wyder, Elsevier (2005).L. Comez, S. Corezzi, G. Monaco, R. Verbeni, D. Fioretto.Non-ergodicity in locally ordered systems in proximity of the glass transition.ESRF Highlights, (2005).S. Erokhina, V. Erokhin.Thin aggregated layer of semiconductor nanoparticle,in Proceedings of the International School on Advanced Material Science and Technology.2002 Jesi, Ancona (Italy), Eds. S. Dobatkin and F. Rustichelli, (2004).S. Erokhina, V. Erokhin.Aggregated layers of semiconductor nanoparticles formed in Langmuir-Blodgett films,in Supramolecular Engineering of conducting materials.M.K. Ram (ed.), Research Signpost, pp. 224-235 (2005).F. A. Gorelli, M. Santoro, R. Bini, G. Ruocco, S. Scandolo, W. A. Crichton.Un vetro di anidride carbonia.Scienza on Line, 30, Anno 3, 17 Luglio 2006.C. Masciovecchio, A. Gessini, S. Di Fonzo, S. C. Santucci, L. Comez, D. Fioretto.Dynamics of disordered systems by inelastic ultra violet scattering.Research Highlights, Elettra, Trieste, (2005).K.L. Ngai, R. Casalini, S. Capaccioli, M. Paluch, C. M. Roland.Dispersion of the Structural Relaxation and the Vitrification of Liquidspp. 79-138 in Fractals, Diffusion and Relaxation in Disordered Complex Systems,Advances in Chemical Physics 133, Wiley, New York (2006)M. Santoro, J. Li, V. V. Struzhkin, H.-K. Mao, R. J. Hemley.In situ raman spectroscopy with laser-heated diamond anvil cells,in Advances in high pressure techniques for geophisical applications.Eds. J. Chen, Y. Wang, T. S. Duffy, G. Shen and L. P. Dobrhinetskaya, Elsevier (2005).T. Scopigno.La transizione vetrosa.KOS 28, 232- 233 (2005).T. Scopigno, G. Ruocco.La transizione vetrosa.Scienza on Line, 20, Anno 2, 17 Settembre 2005.F. A. Gorelli, M. Santoro, R. Bini, G. Ruocco, S. Scandolo, W. A. Crichton.Un vetro di anidride carbonica.Scienza on Line, 30, Anno 3, 17 Luglio 2006.A. Taschin, M. Ricci, R. Torre, A. Azzimanni, C. Dreyfus, R. M. Pick.Transient grating experiments in supercooled liquids.Eds. S. J. Roska and V. P. Zhelemy, Kluwer Acc. Pub. 259.SOFT Scientific Report 2004-06142

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DisseminationSOFT Scientific Report 2004-06144

Contributions to Conferences20043rd Int. Conference on “Broad Band Dielectric Spectroscopy and its Applications”,The Netherlands (2004)• C. Gambi Dielectric Spectroscopy by differential measurements in transmission lineson sodium dodecyl sulfate micelles in wate.• S. Capaccioli Identifying the genuine Johari-Goldstein β-relaxation by cooling,compressing, and aging of some typical glass-formersINFMmeeting,Genova - Italy (2004)• L. Comez Non-ergodicity and clustering in a fragile glass former.• C. Mondelli The backscattering spectrometer IN13 at ILL: present improvements andperspectives• D. Prevosto Connection between fast and slow dynamics in supercooled liquids:evidences from aging experiment• R. Torre Structural relaxation in supercooled waterInternational Workshop on “Dynamics in Viscous Liquids”,München – Germany (March 2004)• S. Capaccioli, Relation between dynamic slowing down and the (isobaric/isothermal)reduction of excess entropy in glass-forming systems• D. Leporini Hierarchic Cage Dynamics and Confinement in Ionomers• B. Ruzicka Gelation in Laponite clay suspensionsXXIII Convegno di Fisica Teorica e Struttura della Materia,Fai della Paganella (TN) – Italy (April 2004)• E. Zaccarelli Vetri e Gels in Sistemi ColloidaliStatPhys 22 Satellite Meeting on “Unifying Concepts in Glass Physics III”,Bangalore – India (June 2004)• D. Leporini Pressure and temperature effects in polymer dynamics• P. Verrocchio Time and length scales in glasses• E. Zaccarelli Gelation Routes in Colloidal SystemsMeeting on “From Hard to Ultrasoft Colloids (HUSC)”,Crete – Greece (June 2004)• E. Zaccarelli Gelation Routes in Colloidal systemsMedicon 2004: Mediterranean Conference on Medical and Biological Engineering,Ischia (NA) – Italy (August 2004)• S. Morante Multi-canonical algorithms for folding processesXXXIV Meeting of the Italian Association of Crystallography (AIC),Roma - Italy (September 2004)• A. Di Cicco XAS Reverse Monte Carlo refinement of molecular and condensedsystems145SOFT Scientific Report 2004-06

DisseminationXII Liquid and Amorphous Metals conference,Metz - France (2004)• T. Scopigno New insights into the collective dynamics of liquid metals• A. Di Cicco Is there icosahedral ordering in liquid and undercooled liquid metals?XVII Latin American Symposium in Solid State Physics,La Habana - Cuba (Dec 2004)• A. Di Cicco Advances in structural techniques for investigation of materials underextreme conditionsSTATPHYS 22,Bangalore - India (2004)• T. Scopigno Is the fragility of a liquid embedded in the properties of its glass?IXS 2004, 5th Conference on Inelastic X ray Scattering,APS Chicago – USA (2004)• T. Scopigno, Fragility of liquids or fragility of glasses?XVIII Conference of the European Colloid and Interface Society,Almeria – Spain (2004)• S. Sennato Evidence of a disordered arrested state in low density aqueoussuspension of polyelectrolyte-liposome complexes20053rd International Conference on "Physics of Disordered Systems",Gdansk - Poland (September 2005)• A. Di Cicco Liquids under extreme conditions7th Workshop and Topical Meeting on “Novel Optical Materials and Applications”,Cetraro - Italy (June 2005)• C. Conti Walking NematiconsCLEO Europe 2005/IQEC 2005,Munich - Germany (June 2005)• C. Conti Anisotropic spatial solitons and their routing in nematic liquid crystalsSPIE Int. Congress on “Optics an Optoelectronics”,Warsaw – Poland (August 2005)• C. Conti Anisotropic nematicons and their routing in liquid crystalsInternational Quantum Electronics Conference,Tokio – Japan (July 2005)• C. Conti Nonlinear X wavesIEEE/LEOS Workshop on Fibres and Optical Passive Components,Mondello (PA) - Italy (June 2005)• C. Conti Ab-initio simulations of backward second harmonic generation in periodicpoled lithium niobateSOFT Scientific Report 2004-06146

Advanced Solid-State Photonics 2005,Vienna – Austria (2005)• C. Conti Generation of forbidden requencies in nonlinear photonic crystalmicrocavities and their applicationsStatistical Physics of Glasses, Spin Glasses, Information Processing …,Les Houches – France (February 2005)• P. Verrocchio Aging properties of glass formersInternational Conference on “Coherent and Nonlinear Optics”,St. Petersburg – Russia (2005)• C. Conti Wavelength shifting in a photonic band-gap microcavity with an isotropicmedium15th IEEE International Conference on “Dielectric Liquids”,Portugal (2005)• C. Gambi Dielectric spectroscopy by differential measurements in transmission lineson self - associating nanostructuresMarie Curie Network Meeting on “Dynamical Arrest”,Bad Gastein - Austria (January 2005)• F. Sciortino Patchy colloids: strong liquids and colloidal gelation• E. Zaccarelli Colloidal gelation in charged systemsFirst International Workshop on “Neutron Brillouin Scattering”,Perugia – Italy (June 2005)• L. E. Bove High-frequency dynamics in liquid metals• A. Cunsolo Pressure evolution of the single particle dynamics of liquid water• A. De Francesco Biophysics and Neutrons: a gentle probe for gentle materials• A. Orecchini BRISP: a technical overview• G. Ruocco The high frequency acoustic vibrations in glasses: facts and speculations• F. Sacchetti The new thermal neutron spectrometer BRISP – The physics at smallmomentum transfer in complex systems• T. Scopigno Microscopic dynamics in liquid metals: uncertainties and challengesInt.Workshop on “Classical and Quantum Simulations in Chemical and Biological Physics”,Dresden – Germany (June 2005)• S. Morante The free energy of peptides binding to metal ionsMMDmeeting,Genova – Italy (June 2005)• P. Verrocchio Critical behaviour of simple glass formers6th EPS Liquid Matter Conference,Utrecht – The Nederland (July 2005)• S. Corezzi Clustering, glass transition and gelation in a reactive fluid• F. Sciortino Cluster Phases, Gels and Yukawa Glasses in charged colloid-polymermixtures• T. Scopigno Hard sphere like dynamics in a non hard sphere system• S. Sennato Equilibrium particle aggregates in attractive colloidal suspensionsWorkshop on "Neutrons in Biology",Grenoble - France (September 2005)• A. Paciaroni Dynamics of proteins embedded in amorphous glassy matrices147SOFT Scientific Report 2004-06

DisseminationConference on "new proton conducting membranes and electrodes for PEM FCs",Assisi - Italy (October 2005)• A. Paciaroni Temperature dependent dynamics of water confined in NafionmembranesWorkshop on "Nanoscience & Nanotechnoology",Frascati (RM) - Italy (November 2005)• A. Paciaroni Dynamics of water confined in fuel cell Nafion membranes with andwithout nanofillerComputer Simulations of attractive particles,Le Mans – France (November 2005)• C. De Michele MD code for hard-bodies• F. Sciortino Patchy Colloids• E. Zaccarelli Gelation in charged colloidsXIX Conference of the European Colloid and Interface Society,Geil – Norvegia (2005)• S. Sennato Thermodynamic and structural properties of mixed DOTAP/DOPEliposomes: charge renormalizationGordon Research Conference on “Elastomers, Networks and Gels”,New London, New Hampshire – USA (July 2005)• D. Fioretto Clustering, Glass Transition and Gelation in a reactive fluid5th International Discussion Meeting on “Relaxations in Complex Systems”,Lille – France (July 2005)• R. Angelini Orientational disorder in the high frequency dynamics of plastic crystals:the case of 1-cyanoadamantane• S. Capaccioli The Effect of Pressure on Structural and Secondary RelaxationDynamics of Glass-Forming Systems Studied by Means of Dielectric Spectroscopy• L. Comez Ergodic to non-ergodic transition in liquid with a local order• S. Corezzi Dynamical arrest in a chemically reactive fluid• D. Leporini The deep structure of the energy landscape and the location of criticaltemperatures in supercooled liquids and polymers: new insights from high-fieldelectron paramagnetic resonance studies• A. Orecchini BRISP: A New Thermal-Neutron Spectrometer for Small-Angle Studiesof Disordered Matter• G. Ruocco Propagation and Attenuation of Nanometer Wavelength Sound Waves inGlasses• F. Sciortiono Gels in colloidal systems• T. Scopigno Vibrational dynamics and viscous flow in glass forming materials• A. Taschin Transient grating experiment on supercooled water• R. Torre Time-resolved spectroscopy with Free Electron Laser pulses• E. Zaccarelli Cluster Phases, Gels and Glasses in Colloidal SystemsXX Congress of the International Union of Crystallography,Florence – Italy (August 2005)• D. Fioretto, Dynamics of Glassy Materials by High Resolution Inelastic X-rayScatteringARW NATO “Soft Matter under Exogenic Impacts”,Odessa – Ukraina, (October 2005)• S. Capaccioli Vitrifying by compression: α- and β-relaxation dynamics of glassformingsystems under high pressureSOFT Scientific Report 2004-06148

Application of Scattering Methods to the Investigation of Soft Condensed Matter,Florence – Italy (November 2005)• G. Ruocco Aging and flow in a complex fluid• F. Sciortino Dynamics in a primitive model for water2nd Workshop on “Inelastic Neutron Spectrometers” (WINS 2005),Cairns – Australia (December 2005)• A. Orecchini et al The new Brillouin Spectrometer BRISPICNS05, International Conference of Neutron Scattering,Sydney, Australia (November 2005)• C. Mondelli Investigation of structure of vitreous B2O3 and alkali borates: neutronscattering and simulationsMiniworkshop for Soft Matter Under Exogenic Impacts,Budapest - Ungheria (December 2005)• S. Capaccioli Dielectric Spectroscopy under High PressureColloquium of the Austrian Physical Chemical Society,Vienna - Austria (October 2005)• F. Sciortino Cluster Phases in Colloidal SystemsAMOLF Colloquia,Amsterdam – The Nederland (Noveber 2005)• F. Sciortino Mechanisms of dynamic arrest at low packing fraction: cluster phases,gels and Yukawa glasses in charged colloid-polymer mixtures3rd International Workshop on “Complex Systems”,Sendai – Japan (November 2005)• P. Verrocchio Finite-size scaling in glass formers2006Workshop on “Dnamical Phenomenon in Soft Matter”,Grenoble – France (February 2006)• G. Ruocco Aging and flow in a complex fluidJSRC5, 5th meeting Soleil Région Centre,Orléans - France (March 2006)• A. Di Cicco Local ordering in liquids under extreme conditionsWorkshop on "dynamics in confinement",Grenoble - France (2006)• A. Paciaroni Temperature dependent dynamics of water confined in Nafionmembranes. A neutron scattering studyWorkshop on "Neutron Scattering Highlights on Biological Systems",Taormina (ME) - Italy (October 2006)• A. Paciaroni Conditioning action of the environment on the dynamics of biomoleculesstudied through elastic neutron scattering• C. Mondelli Study of dynamical transition in disaccharide/water mixtures149SOFT Scientific Report 2004-06

DisseminationX International workshop on “disordered systems”,Molveno (TN) - Italy (March 2006)• L. Angelani A glassy model for random lasers• R. Angelini Inverse melting, over-heating and glass transition• B. Ruzicka New results on Laponite Phase Diagram• S. Capaccioli Cooperative and local relaxation dynamics of glass-forming systemsstudied by dynamic dielectric susceptibility under cooling and compressing• S. Caponi Ergodicity breaking in strong glass-former systems• S. Corezzi Bond-induced static and dynamic evolution in chemically reactivemixtures: IXS experiments and simulations• A. Cunsolo Anomalous behaviour of the single particle dynamics of liquid water• A. Di Cicco Local ordering in liquid metals under extreme conditions• D. Leporini Fast dynamics of glassy polymers: evidences from high-field ElectronParamagnetic Resonance of molecular guests?• A. Orecchini Time-of-flight measurements with the new Brillouin Spectrometer BRISP• B. Rossi Vibrational Dynamics of Inclusion Complexes by Raman Scattering: AnExperimental and Numerical Study• G. Ruocco High Frequency dynamics in metallic glasses• F. Scarponi, Lambda transition in liquid sulphur• T. Scopigno, Infrared Photon Correlation Spectroscopy: a novel experimentaltechnique for the investigation of dynamics in viscous liquids• P. Verrocchio Specific heat of glass formersActa Biophysica Romana,Roma – Italy (February 2006)• S. Morante Ab Initio Simulations of the Cu Binding Site of the Prion Protein• S. Morante Analysis of vesicle shape16 th ESRF User’s Meeting,Grenobe – France (2006)• L. Comez Non-ergodicity in Locally-ordered Systems in the Proximity of the GlassTransitionWorkshop on “Applications of Paris-Edinburgh Cells” (APEC 2006),Paris - France (March 2006)• A. Di Cicco X-ray diffraction and electroresistance measurements using laboratoryequipmentsFrom Computational Biophysics to Systems Biology 2006,Juelich - Germany (June 2006)• S. Morante Ab initio simulations of Cu binding sites in the N-terminal region of PrP5 th Workshop on “Viscous Liquids and the Glass Transition”,Roskilde - Denmark (May 2006)• S. Capaccioli Cooperative and local dynamics in glass-forming systems: new insightsfrom high pressure experimentsXIII SILS Conference,Napoli – Italy (July 2006)• E. Principi Metastable Bi under extreme conditions investigated by XAS• R. Gunnella Kaleidoscopic structures of MBE and implanted Mn:Ge alloys studied byEXAFSSOFT Scientific Report 2004-06150

2nd International Workshop on “Dynamics in Viscous Liquids”,Mainz - Germany (April 2006)• R. Angelini Inverse melting, over-heating and glass transition• F. Ianni Liquid and solid phases in a soft glassy colloidal suspension under shear• D. Leporini The exponential distribution of the landscape energy-barriers and the fastdynamics of glassy polymers: evidences from high-field Electron ParamagneticResonance of molecular guests?• T. Scopigno Infrared Photon correlation Spectroscopy: a novel experimentaltechnique for investigation of dynamics in viscous liquids• E. Zaccarelli Gel to glass transition in a limited valency colloidal systemXVII Congresso Nazionale della SIBPA,Palermo - Italy (September 2006)• S. Morante Analysis of vesicle shapeCongresso della Società Italiana di Fisica,Torino - Italy (Settembre 2006)• C. Conti Glassy behavior of light in random lasers• R. Torre Dynamic processes in supercooled water by time-resolved spectroscopy4 th International Dielectric Society and9 th International Conference on Dielectric and Related Phenomena,Poznan - Poland (September 2006)• S. Capaccioli Dynamics of liquid crystals and polymer melts under shear flow studiedby the rheo-dielectric techniqueNgai Fest,Pisa - Italy (September 2006)• S. Capaccioli Temperature, Density, Connectivity effect on Oligomer and PolymerDynamics• G. Ruocco Laponite and the coupling model4th workshop on “non-equilibrium phenomena in supercooled fluids, glasses,…”,Pisa -Italy (September 2006)• S. Capaccioli Temperature, Density, Connectivity effect on Oligomer and PolymerDynamics• N. Ghofraniha Aging of the Nonlinear Optical Susceptibility in Soft Matter• M. Plazanet -Unexpected behaviour of alpha-cyclodextrin solutions.• T. Scopigno Tackling the lambda-transition in Sulphur by InfraRed Photon CorrelationSpectroscopy• E. Zaccarelli Muiitple glass transitions in star polymer solutionsVI International Electrokinetics Conference,Nancy – France (2006)• S. Sennato Polyion-liposome self assembly: charge inversion and counterion releaseXX Conference of the European Colloid and Interface Society,Budapest – Ungheria (2006)• S. Sennato Polyion-liposome self assembly: charge inversion and counterion releaseElettra XIV users' meeting, workshop on “Science at high pressures”,Trieste - Italy (November 2006)• A. Di Cicco Recent advances in x-ray absorption and diffraction high-pressuremeasurements of polymorphic metals at high temperature151SOFT Scientific Report 2004-06

DisseminationXAFS13, 13 th International Conference on “X-ray Absorption Fine Structure”,Stanford - USA (July 2006)• A. Di Cicco Local ordering in disordered systems under extreme conditionsWorkshop on “Patchy colloids, proteins and network forming liquids:analogies and new insights from computer simluations”,Lyon – France (June 2006)• E. Bianchi Phase diagram of patchy particles: empty liquids and ideal gels• F. Sciortino Dynamics in patchy colloids and network-forming liquids: gels andglasses• E. Zaccarelli Limited-Valency Models for colloidal systemsMarie Curie Network Meeting on “Dynamical Arrest”,Lugano - Svizzera (April 2006)• E. Zaccarelli Cluster phase in colloids and proteins: experiments and simulationsMRS 2006 Spring Meeting,San Francisco – USA (April 2006)• F. Ianni Relaxation of Aggregates in a Jamming Colloidal Suspension After ShearCessation• E. Zaccarelli Cluster phase, gel and glass formation in colloidal systemsConvegno annuale della SISN,Sirolo - Italia (2006)• M. Plazanet Unexpected behaviour of alpha-cyclodextrin solutions• A. Paciaroni Uso di neutroni nello studio delle proprietà delle celle a combustibileC. Mondelli Study of the relation between the mesoscopic structure of cellulose andpaper degradation by small angle neutron scattering9th Lahnwitzseminar on calorimetry:“Transitions far from Equilibrium- Super-heating; Super-cooling”Warnemunde - Germany (May 2006)• R. Angelini Inverse melting, over-heating and glass transitionCONTENTGrenoble – France (July 2006)• A. Cunsolo BRISP: a new tool to investigate the high frequency dynamics ofdisordered systemsUser meeting of the excitation group in ISIS,Rutherford Appleton Laboratory – UK (August 2006)• C. Mondelli Inter-multiplet and intra-multiplet transitions in magnetic clustersSatt13 “Superconduttività ad alta temperatura critica"Sestri Levante -Italia (March 2006)• L. Capogna Magnetic resonance modes in highly overdoped BSCCOSOFT Scientific Report 2004-06152

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DisseminationOrganization of SchoolsA relevant training activity has been also carried out very successfully hosting post-docs andPhD students from various Italian groups at ILL. During their stage at the ILL, besidescarrying out their own research projects, they have been actively involved in thedevelopment and upgrade of IN13 at different stages giving thus important contributions tothe commissioning of new instrument parts as well as developing software codes for theircontrol and for data reduction and analysis IN13 plays also an active role in formingstudents: stages have been organised for Italian students at the end of their undergraduatecareer (Laurea Triennale) providing short training projects on both scientific andinstrumental subjects. Stages for degree and PhD students at the ILL were similarlysuccessfully organized and carried out with the aim of introducing them to the new Brillouinspectrometer BRISP. Part of the participants was directly involved in the development andsetting up of instrument devices as important as the BRISP monochromators andhoneycomb collimators, and all of them took active part in real neutron experiments relatedeither to scientific topics investigated by neutron Brillouin scattering, or to neutron tests ofthe BRISP components.A second dissemination activity regarding neutron scattering was successfully carried out bymeans of the initiative 'Giornate Didattiche', held in Sirolo (Ancona) at the end of June2005. This initiative is based on a short three days’ course which, in 2005, was devoted tothe presentation to young scientists of the perspectives of neutron scattering in magnetism,in connection with other techniques in the field. This course was reserved to Italian studentsand the lecturers were Italian scientists. A total of 22 students attended the course and 15speakers gave presentation of basic magnetic neutron scattering and of basic magnetism,including new materials and technologies.SOFT Scientific Report 2004-06154

Organization of International Conferences and WorkshopFirst International Workshop on Neutron Brillouin ScatteringPerugia, Italy (June 2005).F. Barocchi, E. Guarini, U. Bafile, F. Sacchetti, J.-B. Suck.XII Congresso SILS - Società Italiana di Luce di SincrotroneCamerino, Italy (July 2004)E. Paris, A. Di Cicco, R. Gunnella, E. Principi, M. Minicucci, G. Giuli.V edizione Acta Biophysica Romana (ABR).Roma, Italy (February 2006).S. Morante.1Oth International Workshop on Disordered Systems.Molveno, Italy (March 2006)G. Viliani, A. Fontana.CECAM workshop on Patchy Colloids, Proteins and Network Forming Liquids:Analogies and new insights from computer simulations.Lyon, France (June 2006)E. Zaccarelli, F. Sciortino.XVIII Congresso Nazionale della Società Italiana di Biofisica Pura e Applicata.Palermo, Italy (September 2006).S. Morante.Ngai Fest, satellite of 4th workshop on non-equilibrium phenomenain supercooled fluids, glasses and amorphous materialsPisa, Italy (September 2006)S. Capaccioli.4th workshop on non-equilibrium phenomenain supercooled fluids, glasses and amorphous materials,Pisa, Italy (September 2006)D. Leporini.155SOFT Scientific Report 2004-06

DisseminationSoft Annual WorkshopsEvery year, in the late autumn, Soft members join for a long weekend (Friday to Sunday) tosummarize the activities performed during the previus months and to establish the plane ofaction fo the following year. Beside the general discussion, lasting for a full half day, themeeting host different short scientific presentation (20’ each) delivered by the young Softmembers.These meetings took place at:2004 – Palazzina Uzielli, Vinci (FI)2005 – Hotel Duca degli Abruzzi, L’Aquila2006 – Palazzo Ducale, Camerino (MC)SOFT Scientific Report 2004-06156

Pictures from the last Soft meeting,Camerino (MC), November 2006.(by Andrea Giugni)157SOFT Scientific Report 2004-06

DisseminationSoft WebSiteThe Web Site of Soft has been renewed. The new version (powerd by S. Erriu) will be online in the firs days of 2007, its address is http://www.crs-soft.it/SOFT Scientific Report 2004-06158

AwardsSimona SennatoPremio Ricerca - Innovazione 2005 promosso dal Business Innovation Centre (BIC) delLazio, per il progetto Poly-Electro-Somes (PESo): a new delivery system for controlledmulti-drug release.Emanuela Zaccarelli2006 Marie Curie Network on Dynamical Arrest Prizes for Young Researchers.159SOFT Scientific Report 2004-06

DisseminationContactsINFM-CNR Resarch and Development Center SOFTc/oDepartment of PhysicsUniversity of Rome “La Sapienza”Piazzale Aldo Moro 2I-00185, Rome, ItalyWeb Site : http://www.crs-soft.it/DirectorProf. Giancarlo RuoccoTel +39 06 49913443Fax +39 06 4463158E-mail giancarlo.ruocco@roma1.infn.itWeb site http://glass.phys.uniroma1.it/ruocco/Html/gcr.htmlSecretariatDr. Laura LarotondaTel +39 06 49913433Fax +39 06 4463158E-mail laura.larotonda@phys.uniroma1.itQuesto Report e’ stato realizzato a cura di Daniele Fioretto e Giancarlo RuoccoSOFT Scientific Report 2004-06160

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