Inelastic scattering from core electrons: A multiple scattering approach

Abstract

The real-space multiple-scattering approach is applied to model nonresonant inelastic scattering from deep core electron levels over a broad energy spectrum. This approach is applicable to aperiodic or periodic systems alike and incorporates ab initio, self-consistent electronic structure and final state effects. The approach generalizes to finite momentum transfer a method used extensively to model x-ray absorption spectra (XAS), and includes both near-edge spectra and extended fine structure. The calculations can be used to analyze experimental results of inelastic scattering from core electrons using either x-ray photons or electrons. In the low momentum transfer region (the dipole limit), these inelastic loss spectra are proportional to those from XAS. Thus, their analysis can provide similar information about the electronic and structural properties of a system. Results for finite momentum transfer yield additional information concerning monopole, quadrupole, and higher couplings. Our results are compared both with experiment and with other theoretical calculations.