X-ray absorption at the Ca<i>K</i>edge in natural-garnet solid solutions: A full-multiple-scattering investigation

Abstract

We present an x-ray absorption spectroscopy study at the Ca K edge in several natural-garnet materials with calcium content ranging between 0.2 and 2.9 atoms per formula unit. Comparison of experimental spectra to theoretical calculations based on multiple-scattering theory provides a reliable tool to monitor local environment modifications around the Ca site along the series. Throughout the analysis, special attention has been devoted to determine both the minimum size of the simulation system able to reproduce all the experimental x-ray absorption near-edge structure features, and the best choice for the exchange-correlation contribution to the final-state potential of the photoabsorption process to be used in the ab initio calculations.