Theoretical investigation of Na adsorption on the Al(111) surface

All-electron, full-potential thin-film calculations with the linear-combination-of-Gaussian-type orbitals-fitting function technique are used to determine the energy required to form an ordered (3 × 3) R30° overlayer of Na on the Al(111) surface. Two distinctly different types of adsorption are considered; substitutional adsorption after initial formation of an ordered array of surface vacancies and normal (nonsubstitutional) adsorption at sites with hcp symmetry. The present results for the surface vacancy formation energy, adsorption energies, and adatom-substrate bond lengths are all in good agreement with the results of previous norm-conserving ab initio pseudopotential calculations.