To wet or not to wet? Dispersion forces tip the balance for water-ice on metals

Despite widespread discussion, the role of van der Waals dispersion forces in wetting remains unclear. Here we show that non-local correlations contribute substantially to the water-metal bond and that this is an important factor in governing the relative stabilities of wetting layers and 3D bulk ice. Due to the greater polarizability of the substrate metal atoms, non-local correlations between water and the metal exceed those between water molecules within ice. This sheds light on a long-standing problem, wherein common density functional theory exchange-correlation functionals incorrectly predict that none of the low temperature experimentally characterized ice-like wetting layers are thermodynamically stable.