A Set of Molecular Models for Alkaline-Earth Cations in Aqueous Solution

Abstract

New Lennard-Jones plus point charge models are developed for alkaline-earth cations. The cation parameters are adjusted to the reduced liquid solution density of aqueous alkaline-earth halide salt solutions at a temperature of 293.15 K and a pressure of 1 bar. This strategy is analogous to the one that was recently used for developing models for alkali and halide ions so that both model families are compatible. The force fields yield the reduced liquid solution density of aqueous alkaline-earth halide solutions in good agreement with experimental data over a wide range of salinity. Structural microscopic properties (i.e. radial distribution function and hydration number) are predicted in good agreement with experimental and quantum chemical data. The same holds for dynamic properties (i.e., hydration dynamics, self-diffusion coefficient and electric conductivity). Finally, the enthalpy of hydration of the salts in aqueous solution was favorably assessed.