ON THE METALLIC DROPLET MODEL FOR SUCCESSIVE IONIZATION-POTENTIALS OFMETAL-CLUSTERS - RELATIVISTIC ELECTRONIC-STRUCTURE INVESTIGATIONS OF THE ICOSAHEDRAL GOLD CLUSTER (AU-55)

We have carried out relativistic electronic structure calculations on the naked cluster Au55 in icosahedral geometry using the linear combin ation of Gaussian-type orbitals density functional (LCGTO-DF) method. The one-electron level spectrum is discussed and compared to that of t he jellium model which is able to reproduce the s-type level manifold of Au55 only qualitatively. Furthermore, a series of successive ioniza tion potentials and electron affinities of the cluster has been calcul ated. The remarkable agreement of the all-electron LCGTO-DF results wi th those of the metallic droplet model indicates that the naked cluste r Au55 acts like an almost perfect electron reservoir. In this respect a gold particle of about 50 atoms may mark the onset of the metallic regime.