LOCALIZATION OF 3D AND 4D ELECTRONS IN SMALL CLUSTERS - THE ROOTS OF MAGNETISM

The photoelectron spectra of mass-selected negatively charged Ni-n(-) and Cu-n(-) clusters show similarities, which indicate an almost total localization of the Ni 3d orbitals corresponding to a maximum magneti c moment of 1 mu(B) per Ni atom. The similarity between Ni-n(-) and Cu -n(-) vanishes for n > 7 corresponding to an increase in 3d delocaliza tion. The data of Pd-n(-) clusters suggest a Ni-like (''magnetic'') el ectronic structure for n = 3-6 and a Pt-like (''nonmagnetic'') one for n > 15. There are indications that neutral Pd-7 is a closed shell spe cies (spin zero ground state).