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HIGH-RESOLUTION STUDY OF THE LITHIUM INNER-SHELL RESONANCES R. Wehlitz 1 , J.B. Bluett 1 , and S.B.Whitfield 2 1 SRC, UW-Madison, 3731 Schneider Dr., Stoughton, WI 53589 2 Department of Physics and Astronomy, UW-Eau Claire, WI 54702 The resonance region of lithium (58 – 81 eV) was investigated using monochromatized synchrotron radiation and ion time-of-flight (TOF) spectrometry. The photon beam of the PGM undulator beam line passed through the experimental chamber containing vaporized lithium atoms. The lithium ions created were accelerated by a pulsed electric field into the TOF flight tube and detected by a Z-stack of microchannel plates [1]. We have observed the autoionizing resonances to higher principal quantum numbers than in previous experiments [2,3]. Depending on the energy region we have used an energy resolution of 10 meV and 4.5 meV with step sizes as small as 0.5 meV. Several spectra were taken over short energy intervals as indicated by the different colors of the composed spectrum shown in Fig. 1. All spectra were normalized with respect to the photon flux and background corrected. The fit results along with the data of other authors will be presented for the various Rydberg series on the poster. This work was supported by NSF Grant No. 9987638. The SRC is operated under NSF Grant No. DMR-0084402. References: [1] R. Wehlitz, D. Luki, C. Koncz, and I.A. Sellin, Rev. Sci. Instrum. 73, 1671 (2002). [2] G. Mehlman, J.W. Cooper and E.B. Saloman, Phy. Rev. A 25, 2113 (1982). [3] L.M. Kiernan et al., J. Phys. B 29, L181 (1996).
RESONANCE PARAMETERS OF AUTOIONIZING Be 2pnl STATES R. Wehlitz 1 , D. Luki 2 , and J.B. Bluett 1 1 SRC, UW-Madison, 3731 Schneider Dr., Stoughton, WI 53589 2 Institute of Physics, 11001 Belgrade, Serbia and Montenegro While photoionization of helium has been studied thoroughly, beryllium (1s 2 2s 2 ), the next helium-like atom in the periodic table, has been investigated only marginally by comparison. Double excitations in the Be valence-shell region have been studied experimentally as well as theoretically in the past. In these experiments [1,2] vacuum sparks were used to photo-excite and –ionize Be atoms and absorption spectra were recorded on high-sensitive film. In general, for atomic photoexcitation resonances above the first ionization limit, autoionization becomes possible by interaction with one or more single-ionization continua. This leads to an asymmetric resonance profile in the single-ionization cross section. A theoretical description of this process was introduced by Fano [3] and refined later by Shore and Starace. Since autoionization is a consequence of electron correlation, a measurement of the resonance profile for comparison with theory can provide important information towards our understanding of how electron correlations affect a simple system. We will present our autoionization-profile measurements of the Be 2pns (n=3-8) and 2pnd (n=3-5) double excitations [4]. Since the 1s electrons do not actively participate in the autoionization process, Be appears to be a system only slightly more complicated than He. However it is very different from He insofar as the series of autoionization resonances starts immediately above the first ionization threshold (see Fig. 1). Another difference to He is that the Be 2pns resonances are much broader due to a strong coupling to a rather weak continuum. This work was supported by NSF Grant No. 9987638. The SRC is operated under NSF Grant No. DMR-0084402. References: [1] G. Mehlman-Balloffet and J.M. Esteva, Astrophys. J. 157, 945 (1969). [2] J.M. Esteva, G. Mehlman-Balloffet, and J. Romand, J. Quant. Spectroc. Radiat. Transfer 12, 1291 (1972). [3] U. Fano, Phys. Rev. 124, 1866 (1961). [4] R. Wehlitz, D. Lukic, and J.B. Bluett, Phys. Rev. A, in press (2003).
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Welcome to the 36 th SRC Users’ M
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12:20 - 1:10 Lunch 1:10 -1:45 Poste
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Administration Executive Director D
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STATUS OF THE SRC BEAMLINES AND INS
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ACCELERATOR DEVELOPMENTS Ken Jacobs
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HIGH ENERGY RESEARCH POSSIBILITIES
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ATOMICALLY UNIFORM THIN FILMS ON SI
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Page 18 and 19: MANY-ELECTRON EFFECTS ON THE XE 5S
Page 20 and 21: PHOTOELECTRON SPECTROMETRY OF ATOMI
Page 22 and 23: PHOTOEMISSION STUDY OF USb AND UTe
Page 24 and 25: CANADIAN SYNCHROTRON RADIATION FACI
Page 26 and 27: SELF-ASSEMBLY OF BLOCK COPOLYMERS O
Page 28 and 29: A B S T R A C T S
Page 30 and 31: Photoemission spectra, a.u. -0.3 -0
Page 32 and 33: THE INITIAL AND FINAL STATE BANDS I
Page 34 and 35: TRANSITION LAYERS AT BURIED FERROMA
Page 36 and 37: LOW-DIMENSIONAL ELECTRONS AT SILICO
Page 38 and 39: SUBCELLULAR DISTRIBUTION OF MOTEXAF
Page 40 and 41: LINEAR POLARIZATION MEASUREMENTS OF
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Page 46 and 47: Cr and Fe but for these U systems t
Page 48 and 49: [4] G. -H. Gweon, J. W. Allen, and
Page 50 and 51: References [1] S. Cho, Y. Kim, A. D
Page 52 and 53: [3] D. L. Mills, Physical Review B
Page 54 and 55: CHARACTERIZATION OF SULPHATE INTERA
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Page 58 and 59: spatially resolved chemistry of the
Page 60 and 61: THE RELATIONSHIP BETWEEN PHOSPHATE
Page 62 and 63: PHOTOEMISSION STUDIES OF QUANTUM WE
Page 64 and 65: Ag surface state such that it moves
Page 68 and 69: RELATIVE PARTIAL CROSS SECTIONS AND
Page 70 and 71: Christian Ast Max-Planck Institute
Page 72 and 73: David L. Huber Physical Sciences La
Page 74 and 75: Tom Miller University of Illinois a
Page 76 and 77: Eric Wiedemann University of Wiscon
Page 78 and 79: Pete Hagen Phone: (608) 877-2154 Em
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