COMPUTER MODELING OF A MOLYBDENUM-DISULFIDE CATALYST - DENSITY-FUNCTIONAL CALCULATIONS ON MOLYBDENUM-SULFUR CLUSTERS

Preliminary calculations using the Density Functional Theory (DFT) met hod on saturated and unsaturated molybdenum-sulfur clusters which mode l the active site of a molybdenum disulfide catalyst are reported. Cre ating an edge vacancy at molybdenum by removing sulfur atoms causes th e energy of the HOMO to increase; the catalyst is a better electron do nor. At the same time the charge density on basal sulfurs increases en hancing the ability of the basal plane to interact with pi-orbitals o f the thiophene molecule. Changes in the HOMO energies and the charge densities depend on the structure of the catalyst, in particular on th e separation between unsaturated Mo atoms at the active site.