Adsorption of O on Mo(110) surface from first-principles calculation

First-principles calculations based on density functional theory (DFT) have been performed to study O adsorption in on-surface and subsurface sites. For different coverages, hollow site is found to be the most stable on-surface adsorption site. For the subsurface adsorption at the bare Mo surface, the adsorption energies are found to be higher than those at the on-surface sites, suggesting that these sites are less stable. However, the presence of preadsorbed O overlayer enhances the binding energy of subsurface adsorption, particularly for the adsorption of O at octahedral site. Further, vibrational frequencies, work-function and density of states are presented for O adsorption in on-surface sites.