Oxygen Molecule Dissociation on the Al(111) Surface

The dissociative adsorption of the O₂ on the Al(111) surface is studied using ab initio calculations based on density-functional theory. In the sticking probability experiments an activation barrier for the O₂ dissociation exists, but our calculations predict a barrier only for one trajectory. Also our results do not support the model of charge transfer from the surface to the molecule as a bond breaking mechanism. Instead, the increasing hybridization between O₂ orbitals and Al states, when the adsorbate approaches the slab, is significant for the dissociation.