Oxygen K-edge in vanadium oxides: simulations and experiments

摘要

Band-structure (BS) calculations of the density of states (DOS) using the full potential angmented plane waves code WIEN97 were performed on the four single-valence vanadium oxides VO, V_2O_3, VO_2 and V_2O_5. The DOS are discussed with respect to the distortions of the VO_6 octahedra, the oxidation states of vanadium and the orbital hybridisations of oxygen atoms. The simulated oxygen K-edge fine structures (ELNES) calculated with the TELNES program were compared with experimental results obtained by electron energy-loss spectrometry (EELS), showing good agreement. We show that changes in the fine structures of the investigated vanadium oxides mainly result from changes in the O-p DOS and not from the shift of the DOS according to a rigid band model.