First-principles study of the water structure on flat and stepped gold surfaces

The geometric structure and electronic properties of flat and stepped gold–water interfaces have been addressed by periodic density functional theory (DFT) calculations. This work was motivated by a recent electron energy loss spectroscopy study [H. Ibach, Surf. Sci. 604 (2010) 377] indicating that the structure of a water layer on stepped Au(511) differs significantly from the one on Au(100). Based on ab initio molecular dynamics simulations, the measured spectra have been reproduced and linked to the geometric arrangement of the water molecules. Furthermore, we find a strong polarization of the water layers which contributes to the water-induced work function change of the substrate.