MECHANISMS OF ISLAND FORMATION OF ALKALI-METAL ADSORBATES ON AL(111)

Using density functional theory total-energy calculations we investiga te the chemisorption of Na and K alkali metals on the (111) surface of aluminum from very low coverages (THETA = 1/16) up to a full monolaye r. The calculations predict site changes of the adsorbate atoms, as we ll as a condensation into islands with increasing coverage. Some proce sses are activated, which implies a possibly irreversible temperature dependence. This is shown to have important consequences for the cover age dependence of the work function change.