Hot-atom O2 dissociation and oxide nucleation on Al(111) -: art. no. 176104

We propose an atomistic model for the nucleation of aluminum oxide on the Al(111) surface derived from first principles molecular dynamics simulations. The process begins with the dissociative adsorption of O-2 molecules on the metal surface, which occurs via a hot-atom mechanism driven by the partial filling of the sigma* antibonding molecular orbital of O-2. During the subsequent hyperthermal motion, O atoms can be spontaneously incorporated underneath the topmost Al surface layer, initiating the nucleation of the oxide far below the saturation coverage of one (1x1) O adlayer.