Study of MoO3 (010) surface clusters by ab initio HF approaches

The clusters Mo2O11H10, Mo3O16H14 and Mo7O32H22 of MoO3 (0 1 0) surface wer e studied by using ab initio HF approaches. The geometry of each cluster wa s fully optimized at RHF or UH/IMINI/ECP-SBK level of theory. The bonding p roperties, electronic structures and orbital populations of structurally di fferent oxygens were obtained. It was shown that there exist some differenc es in the bonding properties between Mo atoms and the different oxygens. Th e symmetrically bridging oxygens exhibit more ionic feature while the termi nal oxygens are more covalent. Moreover, information on explaining the acti ve sites for the insertion of oxygen into allylic species in the second ste p of the oxidation processes of propylene to acrolein could be inferred fro m the frontier orbital populations of MoO3 surface cluster. (C) 2000 Elsevi er Science B.V, All rights reserved.