Stability and electronic properties of pure aluminum clusters

Abstract.

The electronic and geometrical structures of neutral and charged clusters Al _N , N<22, are calculated using ab initio density functional theory (DFT). The geometries obtained are in agreement with those of ab initio molecular dynamics. The binding energy is proportional to the inverse of the cluster radius, with a slight overbinding with respect to the experiment. The vertical ionization potentials follow the oscillations found experimentally. The photoelectron density of states for the anions are in agreement with the experimental results. The s, p, and d characters of the Kohn–Sham orbitals are obtained as a function of the size, and it is shown that the s–p hybridization starts at Al₈ both for neutral and anionic clusters. The deeper Kohn–Sham eigenvalues follow the pattern of a spherical jellium-like model. The occupation of the p band is found to be one electron per atom in the cluster; this agrees with experimental results.