ELECTRONIC-STRUCTURE AND CORE LEVEL PHOTOEMISSION SPECTRA IN TIO2 COMPOUNDS

In this paper we first calculate a standard 'linear muffin-tin orbital' band structure (including combined correction and exchange correlation) for TiO2 compounds in rutile structure. The outcoming bands, especially the last valence (mostly O 2p states) and first conduction (mostly Ti t2g states) bands, are fairly hybridized. We then use the information contained in the previously considered density of states to build a simplified electronic structure of TiO2 in order to interpret the Ti core-level photoemission spectra in the simplest way. To achieve this we use the filled band impurity Anderson model which treats the Ti 3d electron-electron correlations and we incorporate the 3d-core hole interaction. Although our model is quite crude from the point of view of the one-electron band structure calculation, it contains many-electron features which can be solved exactly and which are sufficient to roughly describe the satellite structure observed in the core photoemission spectra of TiO2 (as well as related insulating compounds like Li4/3Ti5/3O4 or TiF4, for example).