Electron energy-loss spectroscopy of the OK edge of NbO2, MoO2, and WO2 -: art. no. 245117

Experimental high-energy transmission electron energy-loss absorption spectra from the oxygen K edges of NbO2, MoO2, and WO2 are compared with electronic structure calculations for the relevant empty states, based on the linear augmented plane wave (plus local orbital) method, in the local density approximation. These are also compared with calculations for an idealized rutile structure. The agreement of these ground-state density functional theory calculations (without core-hole effects) for these transition metal dioxides at our resolution of about 1 eV is excellent, and shows in each case an underlying structure consisting of five main peaks, despite differences in local atomic and electronic structure. We find also that shoulderlike features on an e(g) peak can be related to structural distortions induced by the formation of metal-metal bonds.