Molecular dynamics study of the primitive model of 1–3 electrolyte solutions

Abstract

Molecular dynamics simulations at constant temperature have been carried out for the primitive model of 1–3 electrolyte solutions. Thermodynamics, pair distribution functions, and self-diffusion coefficients were computed to examine the electrostatic effects on the structural and dynamical properties. The simulation results were used to evaluate various theoretical equations, namely, the exponential form of Debye-Hückel theory, the mean spherical approximation, and the hypernetted chain approximation. As has been observed for symmetrical electrolytes, the latter turns out to be the best approximation. For asymmetrically charged 1–3 electrolytes, it was found that ionic aggregation significantly influenced the dynamical properties of electrolytes. Coherent motion between highly charged negative ions and positive ions surrounding them was deduced from the time dependence of the velocity autocorrelation functions, particularly at concentrations between 0.4 and 4 total ion molarity.