Systematic variation of the electronic structure of 3dtransition-metal compounds

We have studied the systematic changes of the electronic structure in 3d transition-metal oxides and sulfides within a configuration-interaction cluster model including multiplet effects. Parameters of the model have been deduced from analyses of the 2p core-level photoemission spectra of these compounds. We have calculated the magnitudes of the band gaps, the net d-electron numbers, and the character of doped carriers (and hence of band gaps) within the cluster model. The variation of the calculated magnitudes of the band gaps is in good agreement with experiment, especially with those derived in a recent optical study by Arima et al. of the LaMO₃ series, where M denotes a transition-metal element.