X-ray absorption near-edge structure in alpha-quartz and stishovite:: Ab initio calculation with core-hole interaction

Ab initio calculation of the XANSE/ELNES spectra for alpha quartz and stishovite were carried out using a large-supercell approach that includes the electron-core-hole interaction. Excellent agreements with experimental spectra were obtained for Si-K, Si-L-2,L-3. and O-K edges. The usual interpretation using orbital-resolved local density of states in the conduction band is unsatisfactory. (C) 2001 American Institute of Physics.