Atomic structure and energetics of adsorbed water on the NaCl(001) surface

We have studied the structure and energetics of adsorbed water on the NaCl(001) surface using density-functional calculations within the generalized gradient approximation. We predict a new adsorption structure for the $c(4\ifmmode\times\else\texttimes\fi{}2)$ water bilayer which is energetically favored over the previous puckered hexagonal $c(4\ifmmode\times\else\texttimes\fi{}2)$ structure. Our calculations show that the $1\ifmmode\times\else\texttimes\fi{}1$ monolayer structure (wherein every water molecule binds to each surface cation) is metastable, thereby suggesting that the $1\ifmmode\times\else\texttimes\fi{}1$ structure would be transformed to the more stable $c(4\ifmmode\times\else\texttimes\fi{}2)$ structure which has an increased H-bond interactions between water molecules.