Aqueous Partial Molar Volumes from Simulation and Individual Group Contributions

Abstract

Partial molar volumes (PMVs) for a range of organic solutes in aqueous solution are evaluated from molecular simulations using Kirkwood-Buff theory. Long-range oscillatory variations in the Kirkwood-Buff integrals are suppressed using the techniques of Lockwood, Rossky, and Levy [J.

Communication: Stiffening of dilute alcohol and alkane mixtures with water

“…Subsequently, the water oxygen and solute carbon nuclei can be uniformly smeared over a radius λ. 22,23 For λ's comparable in size to water, oscillations are suppressed and the integrals rapidly converge. Methane-water RDF smearing at 5 • C with λ = 2.0 Å is demonstrated in Figure 3(a), reducing correlations to a comparatively featureless function whose integrated value is unaffected.…”

“…Methane-water RDF smearing at 5 • C with λ = 2.0 Å is demonstrated in Figure 3(a), reducing correlations to a comparatively featureless function whose integrated value is unaffected. 22 Smearing has been used to evaluate solute volumes, compressibilities, and osmotic virial coefficients. [22][23][24] The methane-water association volume, evaluated from the pressure derivative of the smeared RDF at 5 • C and 75 • C, shows distinct features which contribute to the large variation in κ ∞ sol as a function of temperature (Figure 3(b)).…”

“…22 Smearing has been used to evaluate solute volumes, compressibilities, and osmotic virial coefficients. [22][23][24] The methane-water association volume, evaluated from the pressure derivative of the smeared RDF at 5 • C and 75 • C, shows distinct features which contribute to the large variation in κ ∞ sol as a function of temperature (Figure 3(b)). At overlapping, smeared separations ν sw r < 3 Å is negative, indicative of closer water packing against methane with increasing pressure that reduces methane's volume.…”

CHAPTER 9. Partial Molar Volumes of Gases Dissolved in Liquids

“…Using molecular dynamics simulations [183][184][185] in combination with solvent OPLS-AA (Optimized Potentials for Liquid Simulations-All Atom) force field parameters 186,187 and customised force field parameters for the solutes, V LN 2 is computed by the direct method, that is, the volume difference between the pure liquid solvent and a solution containing a single solute molecule is calculated. [188][189][190] In addition, the simulation results may also be used to derive the solute (2)-solvent (1) pair distribution function g 21 (r), 189,191 where r denotes the solute-solvent centre-of-mass distance. At infinite dilution, in the grand canonical ensemble, V LN 2 is given by the Kirkwood-Buff expression 192,193 as is determined only by the spatial solvent structure around the solute and the isothermal compressibility of the pure solvent.…”

Simulated pressure denaturation thermodynamics of ubiquitin

“…The KB expression for the pseudo volume of an infinitely dilute solute, in terms of a spatial integral, G 21 ∞ , over the solute-solvent distribution function, g 21 , is well known [5,7–12,14,22]. However, this is not the most convenient form for irregular shaped objects such as proteins.…”