First-principles study of dissociation processes of O2 molecular on the Al (111) surface

The trajectories of adsorption and dissociation process of O-2 on the Al (111) surface were studied by the spinpolarized ab initio molecular dynamics method, and the adsorption activation energy was clarified by the NEB method with hybrid functionals. Three typical dissociation trajectories were found through simulation of O-2 molecule at different initial positions. When vertically approaches to the Al surface, the O-2 molecule tends to rotate, and the activation energy is 0.66eV. If O-2 molecule does not rotate, the activation energy will increase to 1.43 eV, and it makes the O atom enter the Al sublayer eventually. When the O-2 molecules parallel approach to the Al surface, there is no activation energy, due to the huge energy released during the adsorption process.