Ions in water: From ion clustering to crystal nucleation

The clustering and nucleation of ions in aqueous solutions results from a competition between ion hydration and association. Molecular dynamics simulations of aqueous NaCl solutions are used to investigate ion clustering with a force field adjusted to reproduce experimental properties of the pure NaCl crystal and melt, and of concentrated solutions. The simulation results point to strong sensitivity of the nucleation mechanism to small changes in the force field. We report the numerical evidence for rapid crystal nucleation near saturation or under supercritical conditions.