Structural and Dynamical Properties of an LiCl · 3H2O Solution

Abstract

An MD simulation of an 18.5 molal LiCl aqueous solution was performed with the flexible Bopp-Jancso-Heinzinger model for water, ion-water pair potentials derived from ab initio calcula­tions and the ion-ion interactions described by a potential of Born-Mayer-Huggins (BMH) type. The comparison with a simulation of the same system, where the ion-ion interactions were described by a (12-6) Lennard-Jones + Coulomb potential, demonstrates that such a change affects not only the ion-ion but also the ion-water radial distribution functions significantly, and that the results with the BMH potential conform better to X-ray results. The self-diffusion coefficients for water and the ions are found to be lower by almost one order of magnitude compared with dilute solutions, in good agreement with experimental results. The spectral densities of the hindered translational motions as well as those of the librations and the internal vibrations of the water molecules have been calculated from the simulations through the corresponding velocity autocorrelation functions.