Localization of 3d and 4d Electrons in Small Clusters: The "Roots" of Magnetism.

The photoelectron spectra of mass-selected negatively charged Nin and Cun clusters show similarities, which indicate an almost total localization of the Ni 3d orbitals corresponding to a maximum magnetic moment of 1mB per Ni atom. The similarity between Nin and Cun vanishes for n . 7 corresponding to an increase in 3d delocalization. The data of Pdn clusters suggest a Ni-like (“magnetic”) electronic structure for n ­ 3–6 and a Pt-like (“nonmagnetic”) one for n . 15. There are indications that neutral Pd7 is a closed shell species (spin zero ground state).