STRUCTURAL, ELECTRONIC, AND MAGNETIC-PROPERTIES OF SMALL NI CLUSTERS

The electronic structure and magnetic properties of small Ni-n cluster s (n = 4, 5, 6, 8, 13) are studied at the self-consistent-field multir eference configuration interaction singles level using the intermediat e neglect of differential overlap model Hamiltonian parametrized for s pectroscopy. Results are in agreement with density functional theory c alculations and ab initio calculations for the smaller (n = 4-6) struc tures, Discrepancies develop for the larger (n = 8, 13) structures, an d these discrepancies are discussed. We examine systems and criteria f or the selection of the cluster size that most accurately model hetero geneous catalysts.