title: Hole counts from X-ray absorption spectra.
abstract: The interpretation of X-ray absorption spectra in terms of electronic structure has long been of interest. Hole counts derived from such spectra are often interpreted in terms of free-atom occupation numbers or Mülliken counts. It is shown here, however, that renormalized-atom (RA) and cellular counts are better choices to characterize the configuration of occupied electron states in molecules and condensed matter. A projection-operator approach is introduced to subtract delocalized states and to determine quantitatively such hole counts from X-ray absorption spectra. The described approach is based on multiple-scattering theory (MST) and on atomic calculations of a smooth transformation relating the X-ray absorption spectra to local projected densities of states (LDOS). Theoretical tests for the s and d electrons in transition metals show that the approach works well.
authors.affiliation: Dept. of Physics, University of Washington, Seattle 98195-1560, USA. alex@phys.washington.edu
authors.forename: A L
authors.initials: AL
authors.lastname: Ankudinov
authors.forename: A I
authors.initials: AI
authors.lastname: Nesvizhskii
authors.forename: J J
authors.initials: JJ
authors.lastname: Rehr