Thermodynamically consistent force field for coarse-grained modeling of aqueous electrolyte solution
Abstract
We propose a thermodynamically consistent methodology to parameterize
interactions 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 to
optimize the required interaction parameters. Our results for NaCl aqueous solution show that the
use of mean osmotic coefficient, as well as the activity coefficient of individual ions, allow to
unambiguously determine the Na+-water, cr-water and Na+-cr DPD repulsion parameters. We
propose a simple linear relationship between the hydration free energies· of ions and the ionwater
repulsion parameters that allows the parameterization of the complete series of halide and
alkaline ions. Two different strategies have been used to derive the anion-cation interaction
parameters for halide and alkaline but NaCl. In the first one, parameters are obtained for ail pairs
of ions based on the numericàl optimization of the anion-cation repulsion parameter with respect
to experimental osmotic pressure data. The mean absolute relative deviation between simuJated
and experimental data is then smaller than 4%. Second, we propose a simple, purely predictive
approach to obtain the anion-cation interaction parameters based on the free energy difference of
hydration 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 the
order of 13 %, and with an accuracy better than 6% if small ions (Lt and F) are removed.
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Thermodynamically Consistent.pdf (9.52 Mo)
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Theoretical Insights into the Interaction Suppl Material.pdf (2.79 Mo)
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