Polarization effects at the Uranium L1 and L3 edges Theory and Applications
Polarization effects at the Uranium L1 and L3 edges Theory and Applications
Hennig, C.
Abstract
The polarization dependence of U L1 edge EXAFS spectra is relatively simple because the photoelectron is excited from ground state (l = 0) to one excited state (l = 1). By contrast, the polarization dependence is more complicated at the L2 and L3 edges were the photoelectron is excited from p ground state into final states s (l = 0) and d (l = 2). The EXAFS expression of L2 and L3 edges comprises here pure s, pure d and coupled s-d states. The polarization effect at the U L1 and L3 edges was investigated using a single crystal of Ca[UO2PO4]26H2O. The high symmetry in the equatorial shell allows to compare successful the measurements with the theory. In a second part two types of applications will be discussed. It will be shown, that powder samples have a texture which can lead to an erroneous determination of coordination numbers. A use of the magic angle allows to avoid this problem. A second example will be discussed where the polarization dependency can be used to determine the orientation of actinyl ions sorbed at mineral surfaces.
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Vortrag (Konferenzbeitrag)
Actinides 2005, 04.-08.07.2005, Manchester, Great Britain -
Beitrag zu Proceedings
Actinides 2005, 03.-09.07.2005, Manchester, Great Britain
Recent Advances in Actinide Science, Editors: May, I., Alvares, R., Bryan, N.: The Royal Society of Chemistry 2006, 0-85404-678-X, 716-718
Permalink: https://www.hzdr.de/publications/Publ-7144