Molecular orbital description of catalysis by metal clusters

Extended Hückel and complete neglect of differential overlap (CNDO) molecular orbital calculations were performed for clusters of metallic atoms to determine possible catalytic properties. Data for pure clusters of Ag, Pd, Cd, Cu, and Ni are reported, as well as for alloy systems of PdNi and CuNi. The results indicate the presence of d-band holes in Ni and Pd clusters with a greater amount in Ni. Clusters of Ag and Cd have as low energy form the linear geometry in preference to other three-dimensional geometries. Clusters have a low bond energy (BE) and a different electronic configuration than their bulk metals. The effect of substrates on metal clusters is examined and is shown to be capable of altering electron occupancy of the cluster.