Water adsorption on Pd {100} from first principles

The adsorption of isolated H₂O on Pd {100} has been investigated by density functional theory calculations. We have presented a detailed picture for the adsorption of water monomer on various high-symmetry sites of the surface. We have demonstrated that other d orbitals are responsible for the water adsorptions, in addition to the well-recognized role of dz² orbital. Furthermore, Pd0.2em0ex50.3em0exs state was found to play an essential role in water adsorptions including the favored on-top case. Our findings augment existing knowledge of the electronic nature of water-metal interactions.