Thermodynamically consistent force field for coarse-grained modeling of aqueous electrolyte solution

Carlos Nieto-Draghi (1) , Bernard Rousseau (2)

1 IFPEN - IFP Energies nouvelles
2 LCPO - Laboratoire de Chimie Physique D'Orsay

We propose a thermodynamically consistent methodology to parameterizeinteractions between charged particles inside the dissipative particle dynamics (DPD) formalism.We have used experimental data of osmotic pressure as a function of the salinity in order tooptimize the required interaction parameters. Our results for NaCl aqueous solution show that theuse of mean osmotic coefficient, as well as the activity coefficient of individual ions, allow tounambiguously determine the Na+-water, cr-water and Na+-cr DPD repulsion parameters. Wepropose a simple linear relationship between the hydration free energies· of ions and the ionwaterrepulsion parameters that allows the parameterization of the complete series of halide andalkaline ions. Two different strategies have been used to derive the anion-cation interactionparameters for halide and alkaline but NaCl. In the first one, parameters are obtained for ail pairsof ions based on the numericàl optimization of the anion-cation repulsion parameter with respectto experimental osmotic pressure data. The mean absolute relative deviation between simuJatedand experimental data is then smaller than 4%. Second, we propose a simple, purely predictiveapproach to obtain the anion-cation interaction parameters based on the free energy difference ofhydration energies of anions and cations in the spirit of the law of matching water affinities(LMW A). This approach predict sait properties with a mean absolute relative deviation of theorder of 13 %, and with an accuracy better than 6% if small ions (Lt and F) are removed.

Mots clés: Electrolytes; Dissipative particle dynamics; Interaction parameters; Osmotic pressure; Density; molecular simulation; Thermodynamics

Domaines: Chimie

Carlos Nieto-Draghi, Bernard Rousseau. Thermodynamically consistent force field for coarse-grained modeling of aqueous electrolyte solution. Journal of Physical Chemistry B, 2019, 123 (10), pp.2424-2431. ⟨10.1021/acs.jpcb.8b11190⟩. ⟨hal-02158903⟩