A Kirkwood–Buff derived force field for sodium chloride in water

Abstract

A force field for the simulation of mixtures of sodium chloride and water is described. The model is specifically designed to reproduce the experimentally determined Kirkwood–Buff integrals as a function of salt concentration, ensuring that a good representation of the solution activity is obtained. In addition, the model reproduces many of the known properties of sodium chloride solutions including the density, isothermal compressibility, ion diffusion constants, relative permittivity, and the heat of mixing. The results are also compared to other common sodium chloride force fields.

Kirkwood-Buff analysis of aqueous N-methylacetamide and acetamide solutions modeled by the CHARMM additive and Drude polarizable force fields

“…81,91,94,[96][97][98][99][100][101] The results showed that without introducing polarization good agreement with experimental KB data can be obtained. The present study demonstrated that the polarizable Drude force field, which was not developed by targeting experimental KB data, can also achieve almost the same degree of accuracy compared to KBFF, except for activity derivative and excess Gibbs free energy, which will be the focus in our future force field optimization efforts.…”

“…The low enthalpy of mixing could be a reason for the enhanced self-aggregation in the additive model, as previously shown in aqueous sodium chloride studies by Smith and co-workers. 94 The excess enthalpy with the Drude model was in satisfactory agreement with the experiment results. The fact that Drude model did not reproduce the excess Gibbs energy indicates that problems are possibly present with the excess entropy of mixing, which will be taken into account in future force field optimizations.…”

Preferential interaction parameters in biological systems by Kirkwood–Buff theory and computer simulation

“…[9][10][11][12][13] The use of KB theory is particularly well suited for the analysis of experimental data as it involves no approximations, and for the analysis of simulation data as it only requires the determination of radial distribution functions (rdfs), or coordination numbers, which are easily obtained from simulations. Our previous studies have involved using KB theory to improve the force fields required for computer simulation, [14][15][16][17][18][19] relating simulation data on cosolvent effects to experimental thermodynamic data, [10,11,20,21] and for the interpretation of thermodynamic data on cosolvent effects on biomolecules. [21][22][23][24] Here, we present our latest efforts to use KB theory for the analysis of experimental and computer simulation data relating to the interaction of cosolvents with proteins.…”

On the Theory of Solute Solubility in Mixed Solvents

“…Traditionally, experimental solubility curves have used the common logarithm for the solute solubility, and often the ionic strength in place of concentration. The ionic strength on the molarity scale is defined by, (34) where z + and z − are the charges on the cation and anion, respectively, and c 3 is the cosolvent molarity. Consequently, the use of the indistinguishable ion approach provides, (35) which can be directly compared to the experimentally observed slope.…”