DFT study of oxygen adsorption on W(1Â 1Â 2) surface

Oxygen adsorption on the W(1 1 2) surface has been simulated within DFT in local density approximation. It has been found that at 1 ML coverage, quasi threefold hollow sites, coordinated by two W atoms of the row and one W atom of the next layer, are favored for oxygen atoms. In contrast to the structures of oxygen on the Mo(1 1 2), p(1 × 1) oxygen structure on the W(1 1 2) surface at the one monolayer coverage is predicted. At a half monolayer coverage, preferred sites for oxygen adsorption are found to be the bridge-on-row sites, similarly to results for the p(2 × 1) oxygen structure on the Mo(1 1 2) surface, reported in recent VASP simulations. The stability of the W(1 1 2) surface under oxygen adsorption is discussed as well. The surface relaxation is accompanied by the redistribution of density of states, associated with transformations of surface states.