Symmetry-mediatedH2Odiffusion on Al{100}

Abstract

Based upon the full-electron ab initio calculations, we found orientational preferences and correlation for the atop-to-atop motions of an ${\mathrm{H}}_{2}\mathrm{O}$ on Al{100}, which originates from the symmetry match between an ${\mathrm{H}}_{2}\mathrm{O}$ and the surface square lattice. We have provided theoretical evidence that the favored mechanisms can be classical hopping coupled with either the molecular flipping or in-plane reorientations, with reduced energy barriers compared to those of the simple translational motions; while quantum tunneling assisted motion is not favored for an ${\mathrm{H}}_{2}\mathrm{O}$ via the nearest neighbor diffusion.