Valence-band x-ray photoelectron spectroscopic studies of manganese and its oxides interpreted by cluster and band structure calculations

Valence-band and core-level x-ray photoelectron spectroscopy (XPS) of manganese and its oxides is reported and the valence-band spectra are interpreted by various calculation models. The focus of this paper is on the valence band, which shows significant differences between the oxides of manganese in the formal oxidation states 11, II/III, 111, IV, VI and VII. The study reports the valence band for the metal and the following oxidized forms of the metal: MnO, Mn3O4, Mn2O3, MnO2, K2MnO4 and KMnO4. The difference seen in the valence-band region makes this region appropriate for the surface analysis of manganese compounds and complements the core region, which is often complicated by broad peaks with satellite features. The valence-band region is interpreted by band structure and cluster calculations. It is shown that the differences between the observed spectra and band structure calculations for Mn3O4, Mn2O3 and MnO2 may be a result of the calculation method and not of the highly intense satellites. Copyright (C) 2002 John Wiley Sons, Ltd.