Electronic structures of MoWOy- and MoWOy determined by anion photoelectron spectroscopy and DFT calculations

The anion photoelectron spectra of MoWOy- (y = 2-5) and density functional theory (DFT) calculations on MoWOy- and MoWOy are reported and compared to previous comparable studies on Mo2Oy-/Mo2Oy and W2Oy-/W2Oy. The property governing the structure of the lowest energy MoWOy anion and neutral clusters is the stronger W-O bond relative to the Mo-O bond, which results in the stabilization of structures in which the Mo center is in a much lower oxidation state than the W center. Anion PE spectra show a much larger change in structure between anion and neutral states than what was observed in the pure Mo2Oy- and W2Oy- spectra. DFT calculations show increased single-metal localization of spin with respect to the pure metal oxide clusters. (C) 2009 American Institute of Physics. [DOI: 10.1063/1.3100782]