Transition metal clusters: Electronic structure and interaction with hydrogen and oxides

The self-consistent local spin density theory has been used to explore several aspects of transition metal clusters. The electronic structure and geometry of Ni_n and Pt_n free particles calculated by local spin density (LSD) methods provides at least a reasonable starting point for more intensive and specifically correlated wave function approaches. The chapter emphasizes that a continuum of methods ranging from classical molecular dynamics to highly accurate quantum studies of interelectronic correlation need to be applied to these particles in order to extract the geometries, single particle spectra and many-body cohesive properties being measured currently. The interaction of TM particles with supports and bonding interaction with ligands as simple as hydrogen provides models restricted enough to be amenable to computation by several methods, and close enough to reality, to be compared with experiment. Observations about the magnitude of charge transfer and delocalization of atomic orbitals by interaction with a model substrate may not be quantitatively accurate, but instead form an orientation about the dominant mechanisms and how they may be modified.