First-principles study of H2O diffusion on a metal surface:: H2O on Al{100} -: art. no. 075409

Density functional theory has been used to investigate the adsorption and diffusion of H2O on Al{100}. The favored adsorption site for H2O is the atop site with a binding energy of similar to350 meV. H2O binds only very weakly at bridge sites and does not adsorb at fourfold hollow sites. The activation energies for H2O diffusion depend on the specific orientation of the H2O molecule on the surface and range from 307-327 meV. We show that the barriers for H2O diffusion are consistently larger than the difference in adsorption energies between H2O at the most stable (atop) and next most stable (bridge) adsorption sites.