Water adsorption on clean Ni(111) and p(2x2)-Ni(111)-O surfaces calculated from first principles

A systematic and comprehensive analysis of the adsorption of water monomers, small water clusters, and water thin films on clean and oxygen-predosed Ni(111) surfaces is performed. For the clean Ni surface, the formation of water hexamers (and possibly also incommensurate icelike bilayers) is favored. The total-energy results as well as the calculated vibrational frequencies for water adsorbed on the p(2x2)-Ni(111)-O surface suggest a reinterpretation of recent experimental data [M. Nakamura and M. Ito, Phys. Rev. Lett. 94, 035501 (2005)] in terms of single water monomers adsorbed on top of Ni and the formation of (islands of) an icelike bilayer.