Threshold electronic structure at the oxygen K edge of 3d transition metal oxides: a configuration interaction approach

TL;DR

This paper presents a configuration interaction cluster model to interpret the oxygen K edge X-ray absorption spectra in 3d transition metal oxides, incorporating hybridization and electron correlation for better understanding.

Contribution

It introduces a cluster-based approach that accounts for ground state hybridization and electron correlation, providing improved interpretation of spectral features.

Findings

The model explains experimental spectra of early transition metal oxides.

Differences in ligand hole creation affect spectral features.

The approach aligns well with experimental data.

Abstract

It has been generally accepted that the threshold structure observed in the oxygen K edge X-ray absorption spectrum in 3d transition metal oxides represents the electronic structure of the 3d transition metal. There is, however, no consensus about the correct description. We present an interpretation, which includes both ground state hybridization and electron correlation. It is based on a configuration interaction cluster calculation using a MO6 cluster. The oxygen K edge spectrum is calculated by annihilating a ligand hole in the ground state and is compared to calculations representing inverse photoemission experiments in which a 3d transition metal electron is added. Clear differences are observed related to the amount of ligand hole created in the ground state. Two "rules" connected to this are discussed. Comparison with experimental data of some early transition metal compounds is made and shows that this simple cluster approach explains the experimental features quite well.