title: The Be K-edge in beryllium oxide and chalcogenides: soft x-ray absorption spectra from first-principles theory and experiment.
abstract: We have carried out a theoretical and experimental investigation of the beryllium K-edge soft x-ray absorption fine structure of beryllium compounds in the oxygen group, considering BeO, BeS, BeSe, and BeTe. Theoretical spectra are obtained ab initio, through many-body perturbation theory, by solving the Bethe-Salpeter equation (BSE), and by supercell calculations using the core-hole approximation. All calculations are performed with the full-potential linearized augmented plane-wave method. It is found that the two different theoretical approaches produce a similar fine structure, in good agreement with the experimental data. Using the BSE results, we interpret the spectra, distinguishing between bound core-excitons and higher energy excitations.
authors.affiliation: Department of Physics, Chemistry and Biology (IFM), Linköping University, Linköping, Sweden. weine.olovsson@ifm.liu.se
authors.forename: W
authors.initials: W
authors.lastname: Olovsson
authors.forename: L
authors.initials: L
authors.lastname: Weinhardt
authors.forename: O
authors.initials: O
authors.lastname: Fuchs
authors.forename: I
authors.initials: I
authors.lastname: Tanaka
authors.forename: P
authors.initials: P
authors.lastname: Puschnig
authors.forename: E
authors.initials: E
authors.lastname: Umbach
authors.forename: C
authors.initials: C
authors.lastname: Heske
authors.forename: C
authors.initials: C
authors.lastname: Draxl
mesh_terms: D001608:Beryllium / Q000737:chemistry*; D018011:Chalcogens / Q000737:chemistry*; D011789:Quantum Theory; D056928:X-Ray Absorption Spectroscopy
chemical_list: D018011:Chalcogens; C032777:beryllium oxide; D001608:Beryllium