Computational study of subsurface binding sites of oxygen on Al(111)

Using the same self-consistent linear combination of Gaussian orbitals technique that we previously employed to determine the above-surface initial binding site of oxygen on Al(111), we calculate the energy bands, work function, oxygen binding energy, and Al $2p$ chemical shift of Al(111) films with oxygen underlayers at several sites. The centered octahedral site with a 0.57-{} surface Al relaxation has 1.38 eV greater binding energy than the tetrahedral site suggested by Norman et al. The octahedral site also has a work function and chemical shifts closer to the experimental values than the tetrahedral site. We suggest an alternate interpretation of the experimental data of Norman et al. which is consistent with the octahedral binding site.