THE INITIAL-STAGES OF THE OXIDATION OF AL(111) .1.

Al(111) oxidation has been subjected to numerous studies using surface analysis techniques. Indeed it seems to have been used as a proving g round for techniques to establish the detail each can shed on the dete rmination of the adsorption site of O on a clean Al(111) surface. In t his first detailed ion scattering study of the oxidation of the Al(111 ) surface it has been established that at exposures of up to 100 L alm ost one monolayer of oxygen is adsorbed to the surface. This observati on alone brings into question many models which conclude that the adso rption leads to a surface, and subsurface layer of oxygen. Furthermore , by using shadowing and blocking associated with medium energy ion sc attering (MEIS) it has been possible to exclude the existence of a sig nificant subsurface site at exposures up to 100 L.