Computer simulation of the ionic crystal-water interface

Computer simulation by the molecular dynamic technique has been used to investigate the ionic crystal-water interface. The model consisted of a slab of sodium chloride in contact with water. The Born-Mayer-Huggins potential with the parameters found by Tosi and Fumi were used for the ion-ion interactions, water was modelled by the 'central-force potential' and the ion-water interaction by the potentials proposed by Heinzinger et al. The long range forces were evaluated by the Ewald method. We investigated (a) a system in which only the water molecules were allowed to move while the ions were fixed (b) a system in which all particles could move. Attention was focused on (a) on the behaviour of the water molecules near the crystal surface, and in (b) on the mechanism of the solution process.