Soft Report - Dipartimento di Fisica - Sapienza

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