Debye-Waller effects in Bethe-Salpeter calculations: Bridging the gap between XANES and EXAFS

We present a method to incorporate Debye-Waller effects on core-excitation spectra within frameworks other than real-space, multiple-scattering formulations. The method draws ideas used in multiple-scattering theory to realize effects of variations in interatomic distances, and the method accomplishes this without benefit of the atom-by-atom nature in which multiple-scattering calculations are formulated. We test the method in four metals and one semiconductor over a range of temperatures and compare all theoretical results to experiment. The method is agnostic regarding the source of interatomic distance information, and it should be applicable to a wide range of systems, including systems without crystalline periodicity.