Quantum Statistical Approach to Debye-Waller Factors in EXAFS, EELS and ARXPS IV. Anharmonic Contribution in Spherical-Wave Expression
| Autor: | Takashi Fujikawa, Takafumi Miyanaga, Masaru Yimagawa |
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| Rok vydání: | 1995 |
| Předmět: | |
| Zdroj: | Journal of the Physical Society of Japan. 64:2047-2068 |
| ISSN: | 1347-4073 0031-9015 |
| DOI: | 10.1143/jpsj.64.2047 |
| Popis: | In this work we have developed a new approach based on Brouder's Lie group formulas to include both spherical wave correction and anharmonic vibration effects, which is not limited to isotropic systems. We apply partial summation technique to get a p l a n e w a v e p a r t which does not disappear even for large k R limit, and a s p h e r i c a l w a v e p a r t which disappears for that limit. The former part has just the same cumulants as those used for plane wave EXAFS formulas, however, the latter cannot be reduced to the ordinary cumulants and is closely related to the correction factor due to thermal vibration derived by Rennert within the harmonic approximation. The plane wave part already includes spherical wave effects of photoelectron scattering. Numerical calculations for K-edge EXAFS show that s p h e r i c a l w a v e thermal factors give rise to different phase from p l a n e w a v e p a r t , which can give peak shift in Fourier transformed EXAFS spectra. The polarization dependence is als... |
| Databáze: | OpenAIRE |
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