Monte Carlo simulation of M(+)Cl(-)(H2O)(n) (M=Li,Na) clusters - Structures, fluctuations and possible dissolving mechanism

Monte Carlo simulations of M(+)Cl(-)(H2O)(n) (M = Li, Na) clusters at room temperature using new type of intermolecular potential function were performed to obtain the structural informations under the thermal equilibrium conditions, such as fluctuation of interionic-distance and orientation of water molecules around ion pairs. The lowest-energy geometries of these clusters were water-shared ion pairs, except Li+Cl-(H2O). From Monte Carlo results, we have found that shared water molecules may tend to place between a cation and an anion for their dipole-site stabilization interactions and play an important role for the dissolving process of ion pairs. A possible model for dissolving process of LiCl and NaCl salt into water was proposed.