Theoretical x-ray-absorption near-edge structure (XANES) and extended x-ray-absorption fine structure (EXAFS) of molecular and crystalline KrF2 and gas-phase FeCl2 have been obtained by using a modified X scattered-wave procedure. EXAFS calculations are made in the single-scattering approximation. Effects of multiple scattering near the absorption edge have been investigated by comparing predicted XANES and EXAFS spectra in the near-edge region. Two exchange-correlation potentials, X and energy-dependent Dirac (ED), were incorporated in the EXAFS calculations. Comparison between experimental and theoretical results confirm that the ED potential is more valid for EXAFS spectra. Molecular field splitting as well as resonance coupling were demonstrated by comparing the theoretical XANES of the isolated KrF2 molecule to that of FeCl2. The single-particle XANES calculation of molecular FeCl2 is compared with the experimental crystalline FeCl2 results of Stern.
ASJC Scopus subject areas
- Condensed Matter Physics