Study of (Al2O3)n(O-x) clusters with n <= 16 and x=0, 1, 2 from first principles calculations

Abstract

The ionic and electronic structure of (Al2O3)(n)(O-x) clusters with n less than or equal to 16 and x = 0, 1, 2 is studied by, means of first principles density functional calculations, norm-conserving pseudopotentials and a numerical atomic basis set. The equilibrium geometries have been determined by total energy minimization, starting, with several initial geometries for each cluster size. The trends obtained for the atomic arrangements (structural isomers, coordination numbers, ``disordered'' versus ``ordered'' structures, etc.) and the electronic properties (binding energies, Homo-Lumo gap and dipole moments) are discussed. For most of the oxidized clusters studied here we find that the Homo-Lumo gap and the magnitude of dipole moment of isomeric species can vary drastically.