Interatomic and Intra-Atomic Configuration Interactions in Core-Level X-Ray Photoemission Spectra of Late Transition-Metal Compounds

We theoretically investigate X-ray photoemission spectra (XPS) from transition metal 2p and 3 s core levels in late transition metal compounds in terms of an MX6 cluster model (M=Mn∼Ni; X=halogen or oxygen), paying particular attention to the interplay between the intra-atomic multiplet coupling and covalency mixing effects. In the analysis of 3s-XPS, we also take into account the intra-atomic configuration interaction between 3s13p63dn and 3s23p43dn+l electron configurations. The systematic change of 2p-XPS and 3s-XPS on going from Ni to Mn compounds or from fluorides to bromides is mainly ascribed to that of the charge transfer energy from X to M ion. In the analysis, we show that the final state effects are very important in the 3s-XPS as well as in the 2p-XPS.