Relativistic Corrections to Phase Shift Calculation in the GNXAS Package

Modern XAFS (X-ray Absorption Fine Structure) data-analysis is based on accurate multiple-scattering (MS) calculations of the X-ray absorption cross-section. In this paper, we present inclusion and test relativistic corrections for within GnXAS suite programs, which relevant to treatment signals when atoms with high atomic number are contained into system. We a suitable strategy introducing without altering basic structure programs. particular, realized by modifying only Phagen program calculating cross sections scattering t-matrices selected cluster. The modification incorporates pseudo-Schrödinger Equation (SE) replacing Dirac form. phase-shift have been put in two known molecular crystalline cases: bromine Br2 Pb. Calculations an extended energy range shown be very close non-relativistic case (Br K-edge) while found exceed 25% amplitude phases (Pb L3-edge). Benefits structural refinement using discussed Pb at room temperature.