Winkelabhängige K-Röntgenabsorption und Elektronenstruktur von 3d-Metallverbindungen
The technique of angular resolved K XANES (X-ray Absorption Near-Edge Structure) can differentiate between the angular symmetry of empty electronic states and allows thus a study of local spatial charge distribution in different atomic complexes. The K XANES curves image the unoccupied local densities of states. They can be resolved via a quantitative analysis of numerous angular resolved K XANES spectra of single-crystals into the partial components of particular angular symmetries. Original
... metries. Original studies of angular resolved K XANES performed within this work at the range of monoxides MnO, FeO, CoO, NiO and CuO sustain the applicability of LSDA+U (Local Spin Density Approximation corrected by the Hubbard energy U) for description of strongly correlated 3d insulators. An analysis of different 3d transition metal compounds (TiS2, TiSe2, TiTe2, V2O5, MnO, FeO, CoO, NiO, CuO und CuGeO3) indicates a dominance of p-like contributions to the K absorption pre-edge maximum in the case of earlier 3d metals. The d-like contributions dominate however by the later 3d transition metals. The studies derive the unoccupied d-like states in Mott/charge-transfer insulators to be localised at the shortest Me-O-bonds.