First-principles calculations of x-ray absorption near edge structure and energy loss nearedge structure: present and future

Abstract

Computational methods for theoretical x-ray absorption near edge structure (XANES)and energy loss near edge structure (ELNES) are classified into a few groups.Depending on the absorption (or excitation) edge, required accuracy and desiredinformation, one needs to select the most suitable method. In this paper, afterproviding a map of available computational methods, some examples of first-principlescalculations of XANES/ELNES for selected wide gap materials are given together withreferences. For ZnO, for example, experimental spectra at three edges, Zn K,L3, and O K, including their orientation dependence, are well reproduced by the supercellcalculations with a core hole. Good agreement between theoretical and experimentalspectra of ZnO alloys can also be seen. Theoretical fingerprints are satisfactorily obtainedin this way. However, there are remaining issues beyond ‘good agreements’ which need tobe solved in the future.