Ab initio calculations of inelastic losses and optical constants
  Ab initio approaches are introduced for calculations of inelastic losses and vibrational damping in core level x-ray and electron spectroscopies. From the dielectric response function we obtain system-dependent self-energies, inelastic mean free paths, and losses due to multiple-electron excitations, while from the dynamical matrix we obtain phonon spectra and Debye-Waller factors. These developments yield various spectra and optical constants from the UV to x-ray energies in aperiodic materials, and significantly improve both the near edge and extended fine structure. 
J. J. Rehr, J. J. Kas, M. P. Prange, F. D. Vila, A. L. Ankudinov, L.   W. Campbell, and A. P. Sorini