The impact of charges in force field parameterization for molecular dynamics simulations of deep eutectic solvents

Abstract

The nanoscopic characteristics and macroscopic physicochemical properties of choline chloride:levulinic acid (1:2 mole ratio) deep eutectic solvent are analyzed from molecular dynamics simulations. Considering the ionic character of some of the involved molecules, the influence of several charge schemes in the applied force field parameterization was studied. Assessed charge schemes include atomic charges obtained from wavefunctions (Mulliken, NPA, L?wdin, Mayer), electrostatic potentials (ChelpG, MK), spectroscopic data (APT) and partitioning of the electronic densities (Hirshfeld, VDD, AIM). Molecular dynamics simulations were carried out using these ten charge schemes with the remaining force field parameters being constant. The reported results show the remarkable role of the used charges in the results from molecular dynamics simulations, with large differences both in the predicted macroscopic properties. This work shows the need of using suitable charge models for developing reliable and accurate molecular dynamics simulations of deep eutectic solvent structuring. Charges from electrostatic potentials along to cluster approach should be the most adequate option for developing force field parameterization in deep eutectic solvents.