THEORY OF THE FINE-STRUCTURE IN INELASTIC X-RAY-SCATTERING SPECTRA OF SOLIDS

The method is proposed for calculating the fine structure in inelastic X-ray scattering (IXS) spectra formed due to K-ionization of low-Z atoms in solids. Both the first- and the second-order perturbation theory terms are included to calculate IXS cross-section. The first-order terms proportional to p-LDOS are shown to dominate if the initial photon energy exceeds 2 keV. For lower photon energy and small scattering angles the second-order terms proportional to the s-LDOS provide dominant contributions into the cross-sections which are large enough to be measured experimentally. The expressions are derived which enable one to calculate p-LDOS from the experimental IXS spectra. The p-LDOS of graphite obtained by the experimental IXS spectra and XAS are in good agreement with each other and with the ones obtained by the full multiple scattering method.