Dielectric behavior for saline solutions from renormalized diagrammatically proper interaction site model theory.

We consider the dielectric response of angularly dependent site-site theories for models of aqueous saline solutions. We find that we can use relatively low order approximations of the angularly dependent correlation functions with correct long ranged behavior to obtain good estimates of the dielectric constant for three site water models and simple 1-1 salts. We find that the solution thermodynamics results for this level of theory, as measured by the Kirkwood G integrals and the excess chemical potentials, are in good quantitative agreement with simulation even when the details of the short ranged structure is not as accurately determined.

Solubility Limits in Lennard-Jones Mixtures: Effects of Disparate Molecule Geometries.

In order to better understand general effects of the size and energy disparities between macromolecules and solvent molecules in solution, especially for macromolecular constructs self-assembled from smaller molecules, we use the first- and second-order exact bridge diagram extensions of the HNC integral equation theory to investigate single-component, binary, ternary, and quaternary mixtures of Lennard-Jones fluids. For pure fluids, we find that the HNCH3 bridge function integral equation (i.e.

Solvation and cavity occupation in biomolecules.

Background: Solvation density locations are important for protein dynamics and structure. Knowledge of the preferred hydration sites at biomolecular interfaces and those in the interior of cavities can enhance understanding of structure and function. While advanced X-ray diffraction methods can provide accurate atomic structures for proteins, that technique is challenged when it comes to providing accurate hydration structures, especially for interfacial and cavity bound solvent molecules.

The behavior of ions near a charged wall-dependence on ion size, concentration, and surface charge.

A renormalization of the 3D-RISM-HNC integral equation is used to study the solvent and ion distributions at neutral and negatively charged planar atomistic surfaces. The charge density of the surfaces ranged from 0.0 to 0.

Protein solvation from theory and simulation: Exact treatment of Coulomb interactions in three-dimensional theories.

Solvation forces dominate protein structure and dynamics. Integral equation theories allow a rapid and accurate evaluation of the effect of solvent around a complex solute, without the sampling issues associated with simulations of explicit solvent molecules. Advances in integral equation theories make it possible to calculate the angle dependent average solvent structure around an irregular molecular solution.

Site-renormalised molecular fluid theory: on the utility of a two-site model of water.

We propose a simple, two-site model of water, using the familiar three-site Simple Point Charge (SPC) model as a guide. We briefly examine the resulting dielectric and solvation properties of the bulk fluid, both pure and in a three component mixture of apolar or ionic simple fluid solutes, using integral equation methods. The results confirm a practical utility of this simplified model, and the essential predictive properties of the site-renormalised molecular fluid theory.

A molecular site-site integral equation that yields the dielectric constant.

Our recent derivation [K. M. Dyer et al.

An Integral Equation Study of the Hydrophobic Interaction between Graphene Plates.

The hydrophobic association of two parallel graphene sheets is studied using the 3D-RISM HNC integral equations with several theoretical methods for the solvent distribution functions. The potential of mean force is calculated to study the effects of the aqueous solvent models and methods on the plates as a function of distance. The results of several integral equations (IE) are compared to MD simulations for the same model.

A site-renormalized molecular fluid theory.

The orientation-dependent pair distribution function for molecular fluids on site-site potentials is expanded in a topological analog of the diagrammatically proper site-site theory of liquids [D. Chandler et al., Mol.

Effective density terms in proper integral equations.

Two complementary routes to a new integral equation theory for site-site molecular fluids are presented. First, a simple approximation to a subset of the atomic site bridge functions in the diagrammatically proper integral equation theory is presented. This in turn leads to a form analogous to the reactive fluid theory, in which the normalization of the intramolecular distribution function and the value of the off-diagonal elements in the density matrix of the proper integral equations are the means of propagating the bridge function approximation.

Simple bond length dependence: a correspondence between reactive fluid theories.

Two elementary models of reactive fluids are examined, the first being a standard construction assuming molecular dissociation at infinite separation; the second is an open mixture of nondissociative molecules and free atoms in which the densities of free atoms and molecules are coupled. An approximation to the density of molecules, to low order in site density, is derived in terms of the classical associating fluid theory variously described by Wertheim [J. Chem.