Adsorption and diffusion of H2O molecule on the Be(0001) surface: A   density-functional theory study
  Using first-principles calculations, we systematically study the adsorption behavior of a single molecular H$_{2}$O on the Be(0001) surface. We find that the favored molecular adsorption site is the top site with an adsorption energy of about 0.3 eV, together with the detailed electronic structure analysis, suggesting a weak binding strength of the H$_{2}$O/Be(0001) surface. The adsorption interaction is mainly contributed by the overlapping between the $s$ and $p_{z}$ states of the top-layer Be atom and the molecular orbitals 1$b_{1}$ and 3$a_{1}$ of H$_{2}$O. The activation energy for H$_{2}$O diffusion on the surface is about 0.3 eV. Meanwhile, our study indicates that no dissociation state exists for the H$_{2}$O/Be(0001) surface. 
Shuang-Xi Wang, Peng Zhang, Jian Zhao, Shu-Shen Li, Ping Zhang
cond-mat.mtrl-sci