A first-principles study of Al nSi m−n clusters ( m = 6, 9, 10; n ⩽ m)

Abstract

Equilibrium geometries, binding energies, electronic structures, ionization potentials and electron affinities of neutral Al n Si m − n clusters ( m = 6, 9, 10; n ⩽ m) have been calculated using the Amsterdam Density Functional (ADF) program with TZ2P basis set in conjunction with self-consistent field (SCF) and generalized gradient approximation. The remarkable stability of the clusters with valence electrons corresponding to electronic shell closure is found. The ground-state structures show that Al atom prefers vertex sites in the host Si clusters, which is different from the earlier studies. For Al n Si 9− n and Al n Si 10− n clusters, the energy deviations, ionization potentials and electron affinities show obvious odd–even alternations with the cluster composition. In addition, the ground-state structures of the heteroatomic clusters are different from those of the pure Al or Si clusters. Their symmetries are usually C 1.