First-Principles Modeling Of X-Ray Raman Scattering Spectra

An efficient technique for calculating x-ray Raman scattering spectra at the K edge in the framework of a single-particle theory is presented. It is based on a recursive method to compute the dynamic structure factor as a continued fraction without requiring the explicit calculation of high-lying unoccupied electronic states. Multipole transitions are calculated to provide a full account of the q-dependence of K edges recorded in a series of lithium-bearing reference compounds, namely LiBO2, Li2CO3, Li2O, and LiF. The good agreement obtained between experimental and theoretical spectra validates our approach and provides a solid foundation for analyzing K edges beyond the dipole approximation.