Molecular dynamics simulations of water at NaCl(001) and NaCl(011) surfaces

The characteristics of water molecules near the (001) and (011) faces of NaCl crystals at 298 K were investigated, using classical molecular dynamics simulation. It was found that no ion is dissolved from the crystals into water during 10 ps and so the NaCl(001) and NaCl(011) surfaces without any lattice defect are stable in water, at least within the period of our computer experiments. The successive simulation exhibited that ii water molecules in the first two layers near the crystal surfaces reduce their diffusivity and are regarded as "solidlike", but a slight difference in the features between NaCl(001) and NaCl(011)surfaces causes the significant difference in the interactions between a water molecule and the surfaces, the number of adsorbed layers of water, the positions of water molecules, the perturbation of the hydrogen-bonding network, and the detailed diffusional motion near the surface, and (2) water molecules in the central region of the water lamina confined between the two surfaces can be regarded as bulk with respect to the static propel-ty, but their dynamical properties are still influenced by the existence of the crystal surfaces.