Theory on Extended X-Ray Emission Spectra

抄録

A simple theoretical approach is given to study XAFS-like spectra (extended X-ray emission fine structure, EXEFS) observed in X-ray fluorescence spectra based on one-step quantum mechanical formula derived by Almbladh and Hedin. Electronic relaxation and shake-off processes are crucial to explain the spectral features. Here the “shake-off” processes are different from those found in the typical XPS and XAFS spectra; the “shake-off” electrons are ejected during the fluorescence emission processes. Formal EXEFS formulas derived here are the same as the usually used XAFS formula. However, we should carefully use the phase shifts by taking account of the relaxation effects due to additional core hole production; they should be different from those used in the XAFS analyses. The radial dipole integral should be replaced by the corresponding monopole radial integral in the EXEFS analyses.