A subtle structure evolution of metal-adsorbed water bilayer and the effect of dispersion correction

Based on the density functional theory with dispersion correction, we have carried out a systematic study on the first adsorbed water layer on Au (1 1 1), Pt (1 1 1) and Pd (1 1 1) surfaces. We find that, these systems seem to have a quite smooth potential energy landscape near the ground state, manifested by a few possible low-energy configurations with almost degenerate absorption energy to the ground state. Among them, there is a subtle structure evolution, which is related to the competition between water-water and water-metal interactions. Although the dispersion correction and the choice of exchange–correlation functional may bring some differences, the interesting feature of smooth potential energy landscape remains unchanged. This phenomenon has not been mentioned in similar studies and should not be ignored.