The electronic structure of small nickel clusters

The electronic structure of small nickel clusters (Ni1–Ni6) has been investigated by ab initio SCF and CI calculations. Among others the symmetry broken SCF calculations have been performed for the ionization of the clusters, and it is found that an ionized state resulting from electron removal from a 3d-like orbital is the Fermi level or quite close to the Fermi level. The resulting d hole is shown to localize at one of the constituent atoms. The calculated band structure of the clusters is found to be similar to that of the solid Ni. The calculated first I.P. (Fermi energy with sign changed) is 4.5 eV for Ni1–Ni6, which is favorably compared with experimental results given by Rohlfing and co-workers.