Strongly bonded water monomers on the ice Ih basal plane: Density-functional calculations

The adsorption of water monomers on noncrystallographic sites of the ice Ih basal plane is calculated from first principles. The results presented here do not support previous theoretical findings that state molecular adsorption energies in excess of the bulk cohesive energy. Still, due to an enhanced strength of the surface hydrogen bonds compared to the bulk, the admolecules are found to lower the ice surface energy. For the surface structures investigated here, the monomer adsorption energies are found to be rather insensitive with respect to the detailed microscopic structure of the underlying substrate. The latter, however, determines the adsorption-induced changes of the surface dipole layer.