1982 Volume 3 Issue 1 Pages 17-26
The electronic structure of stoichiometric hydrides TiH2, VH2, ZrH2, and NbH2 with fluorite struture has been calculated using the discrete variational (DV) -Xα method. Clusters studied were [Me6H8] n+ (Me : metal, n=2.6 to 4.0) and [Me4H8]. Although the level structures obtained for the [Me6H8] n+ clusters are generally in accordance with those by previous band calculations, the results are inconsistent with UPS spectra for the Me-H system. On the other hand, Me-H bonding levels for the [Me4H8] cluster are located over 4 to 8eV relative to the Fermi level EF, in good agreement with UPS and X-ray emission measurements. These levels are composed mainly of Me d, p+H1s (4 to 6eV) and Me s, p+H1s (5 to 8eV) hybridizations. The charge states are + (1.3±0.1) for Me and - (0.65±0.05) for H atoms, respectively. The valence band in XPS spectra of the dihydrides are also demonstrated. Applicability of XPS to the investigation on bonding states of the Me-H systems is discussed.
