Elucidating Electronic Structure of Transition Metal Oxide Clusters from Photoelectron Spectroscopy and Electron Structural Calculations

Shenggang Li and David A. Dixon, Department of Chemistry, The University of Alabama

Transition metal oxides (TMOs) form an important class of materials widely employed as industrial catalysts and catalyst supports.  Due to the presence of low-lying electronic states, accurate determination of the ground electronic states of these clusters poses a significant challenge.  Using the CCSD(T) method, we have studied the electronic structure of the neutral and anionic clusters of the group IVB and VIB TMOs in various oxidation states.  Our predicted electron affinities, electron excitation energies, clustering energies, atomization energies, and heats of formation are compared with data from recent anion photoelectron spectroscopic measurement and other experiments.  Simulated photoelectron spectra from accurate Franck-Condon calculations are also compared with experiment.  Such comparison proves essential in accurate determination of electronic structure and energetic properties for these clusters.  We have also benchmarked a larger number of density functional methods for calculating these properties, which will be crucial in applying density functional theory to the study of catalytic reaction mechanism involving these TMOs.

Oral