On the properties of methanolic NaCl solution by molecular dynamics simulations

TL;DR

This study uses molecular dynamics simulations to analyze the microscopic structure and thermodynamic properties of methanolic NaCl solutions, comparing different force fields to evaluate their predictive accuracy.

Contribution

It systematically evaluates various force fields for modeling NaCl in methanol, providing insights into their effectiveness in predicting key solution properties.

Findings

Different force fields vary in accuracy for density predictions.

Structural properties depend on the chosen force field.

Self-diffusion and dielectric properties are sensitive to ion concentration.

Abstract

Isothermal-isobaric molecular dynamics simulations are used to examine the microscopic structure and principal thermodynamic properties of a model solution consisting of NaCl salt dissolved in methanol solvent. Four united atom force fields for methanol are involved. Concerning ion solutes we used the Joung-Cheatham, Smith-Dang models as well as the model from the laboratory of Vrabec. Our principal focus is to evaluate the quality of predictions of different combinations of models for basic properties of these solutions. Specifically, we explored the change of density on molality, the structural properties in terms of various pair distribution functions, the coordination numbers, the number of ion pairs and the average number of hydrogen bonds. In addition, changes of the self-diffusion coefficients of species, the solvent dielectric constant and the evolution of the surface tension with ion concentration are described.