The Be K-edge in beryllium oxide and chalcogenides: soft x-ray absorption spectra from first-principles theory and experiment

摘要: We have carried out a theoretical and experimental investigation of the beryllium K-edge soft x-ray absorption fine structure compounds in oxygen group, considering BeO, BeS, BeSe, BeTe. Theoretical spectra are obtained ab initio, through many-body perturbation theory, by solving Bethe–Salpeter equation (BSE), supercell calculations using core-hole approximation. All performed with full-potential linearized augmented plane-wave method. It is found that two different approaches produce similar structure, good agreement data. Using BSE results, we interpret spectra, distinguishing between bound core-excitons higher energy excitations.