Electronic structure of Ti4Fe2O as determined from ab initio calculations and X-ray spectroscopy studies

The TiLα, FeLα and OKα ultrasoft X-ray emission bands obtained in experiment reflect, respectively, the energy distribution of mainly the Ti3d, Fe3d and O2p electronic states in Ti4Fe2O compound, which is an efficient hydrogen absorber for energy cells. Full and partial densities of electronic states for all atoms constituting the indicated oxide were calculated by a modified method of associated plane waves (APW) using the WIEN2k software package. The APW calculation data for Ti4Fe2O compound as well as superposition of TiLα, FeLα and OKα ultrasoft X-ray emission bands on a single energy scale indicate that O2p states in the oxide are localized mainly near the bottom of the valence band, the major contribution near the ceiling of the valence band belonging to Fe3d and Ti3d states. According to the APW calculation, the major contribution to the bottom of Ti4Fe2O conduction band is made by Fe3d* and Ti3d* states. The APW data for Ti4Fe2O are supported by the cluster calculation performed for this compound using a FEFF82 software package.