Unified interpretation of pre-edge x-ray absorption fine structures in 3d transition metal compounds

Abstract

Here we discuss origin of pre‐edge features in the K‐edge absorption spectra of transition metal atoms in octahedral coordination, in oxides and sulphides. We provide a unifying interpretation on the basis of multiple scattering simulations performed with different cluster models. We find that the pre‐edge features arise due to hybridisation of the orbitals belonging to the central atom with the higher‐shell metal orbitals. The results are obtained by performing multiple scattering simulations with cluster of size equal to the cation‐cation plus the cation‐anion bond lengths in order to ensure that the higher‐shell metal atoms remain in the octahedral coordination. Within this framework, we are able to identify the electronic structure of the metal atoms and the ligand‐field characters looking at position, shape and intensity of the different features observed in the XANES spectra.