Ab initio simulation of core-hole effects on the X-ray absorption near edge structure of GaP

The core-hole effects on X-ray absorption near edge structure (XANES) of GaP with pressure have been investigated using all-electron full potential linearized augmented plane wave method. Four electronic configurations, i.e., ground state (GS), transition state (TS), final state (FS), and Z+1 approximation (Z+1), in the treatment of core-hole have been employed. The calculated results suggest that the experimental spectra are well reproduced by the FS and Z+1 configurations. Our XANES results support the metallic GaP-II has a Cmcm symmetry.