The interaction of oxygen with the α-U(001) surface: an ab initio study

First-principles calculations based on density functional theory have been performed to investigate the adsorption, dissociation and diffusion of oxygen on the alpha-Uranium(001) surface. The results showed that O-2 tends to dissociate followed by the occupation of the two adjacent three-fold hollow sites. The weak molecular adsorption was found for O-2 adsorbed perpendicularly at the top of a uranium (U) atom. The investigation of the dissociation for O-2 from the top site with the O atoms falling into the two adjacent hollow sites indicated the spontaneous dissociation of O-2. The surface diffusion of atomic oxygen between two adjacent hollow sites encountered an activation barrier of 0.55 eV, indicating the slow motion for O on the alpha-U(001) surface.