CHEMICAL TRENDS AND BONDING MECHANISMS FOR ISOLATED ADSORBATES ON AL(111)

Using the self-consistent surface-Green-function method we study the chemisorption of isolated adatoms bonded to the (111) surface of aluminum. In order to identify chemical trends, a group-I group-IV, and group-VII adsorbate is considered. Our study is analogous to that of Lang and Williams with the difference that their substrate was jellium, whereas we take the substrate atomic structure fully into account. The influence of the atomic structure is clearly noticeable in the electronic density of states, charge density, and atomic geometry, but the main (qualitative) conclusions of Lang and Williams are supported by our results. The discussion of the group-I adsorbate is complemented by calculations for periodic adlayers, in order to demonstrate the influence of adsorbate-adsorbate interactions.