Behavior of the aqueous sodium chloride solutions from molecular simulations and theories

Molecular simulations and theories are important tools for studying electrolyte solutions. In this work, molecular dynamics simulations with one of the most widely used force field combination of water and alkali and halide monovalent ion parameters were first conducted for the aqueous sodium chloride solutions to predict density, self-diffusion coefficients and molar conductivity. Then the radial distribu-tion functions were analyzed to obtain the first shell solvation radii and coordination numbers of ions, which were found practically unchanged against concentration. Together with the force field parameters, they were further applied into various molecular theories to predict the Gibbs energy of solvation, static relative permittivity, mean ionic activity coefficients and molar conductivity. It is remarkable to see that the mean ionic activity coefficients and molar conductivity can be predicted with deviations of 1.1 % and 1.4 %, respectively, up to 6 mol/kg H2O.(c) 2022 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).

Automated summary

Molecular simulations and theories were used to study electrolyte solutions. The simulations predicted properties like density, self-diffusion coefficients, and molar conductivity of aqueous sodium chloride solutions. The analysis of radial distribution functions provided information on solvation radii and coordination numbers of ions, which remained practically unchanged with respect to concentration. The predictions made using molecular theories for solvation Gibbs energy, static relative permittivity, mean ionic activity coefficients, and molar conductivity showed good agreement with deviations of 1.1% and 1.4%, respectively, up to 6 mol/kg H2O.