The thermodynamics and structure of hydrated halide and alkali ions

Gibbs free energies were calculated for the gas phase reaction: ion(H 2O)N-1 + H2O(vapour) = ion(H 2O)N for the Li+, Na+, K +, Cl-, and F- ions and for N = 1 to 6. The Monte Carlo method was used to evaluate the appropriate classical expressions of statistical mechanics by employing the intermolecular potential functions recently developed from ab initio Hartree-Fock calculations. Enthalpies and structural information were also calculated. Agreement with experiment is sufficiently good to demonstrate the feasibility of this approach.