Electrostatic contributions properties

It is often the case that the solvent acts as a bulk medium, which affects the solute mainly by its dielectric properties. Therefore, as in the case of electrostatic shielding presented above, explicitly defined solvent molecules do not have to be present. In fact, the bulk can be considered as perturbing the molecule in the gas phase , leading to so-called continuum solvent models [14, 15]. To represent the electrostatic contribution to the free energy of solvation, the generalized Bom (GB) method is widely used. Wilhin the GB equation, AG equals the difference between and the vacuum Coulomb energy (Eq. (38)) ... 

Rheology. Flow properties of latices are important during processing and in many latex appHcations such as dipped goods, paint, inks (qv), and fabric coatings. For dilute, nonionic latices, the relative latex viscosity is a power—law expansion of the particle volume fraction. The terms in the expansion account for flow around the particles and particle—particle interactions. For ionic latices, electrostatic contributions to the flow around the diffuse double layer and enhanced particle—particle interactions must be considered (92). A relative viscosity relationship for concentrated latices was first presented in 1972 (93). A review of empirical relative viscosity models is available (92). In practice, latex viscosity measurements are carried out with rotational viscometers (see Rpleologicalmeasurement). 

Steric and Electrostatic Contributions to the Colloidal Properties of Nonaqueous Dispersions... 

E. R. Lippincott The proposed model is certainly empirical. However, the internuclear potential function used for the terms V1 and F2 may be derived from a quantum mechanical model which lends support to their use in such a treat-ment of hydrogen bond systems. Professor Pauling is quite right in suggesting that the terms Vx and F2 may include some electrostatic contribution, since it is known that the internuclear potential function used correlates properties fairly well for partial polar bonds. Nevertheless the fact that additional terms of the electrostatic type are not needed to describe a number of the important properties of hydrogen bond systems, suggests that the covalent, repulsion and dispersions energy contributions are more important than the electrostatic contribution. 

Since the CM3 charges reproduce the dipole moments very well, they can reproduce also other electrostatic properties. These charges can, in particular, be used in the PB and GB models (see next sections). These models provide electrostatic reaction field energies of the molecular environment, in particular, giving electrostatic contributions to solvation energies. 

Abstract Analytical solution of the associative mean spherical approximation (AMSA) and the modified version of the mean spherical approximation - the mass action law (MSA-MAL) approach for ion and ion-dipole models are used to revise the concept of ion association in the theory of electrolyte solutions. In the considered approach in contrast to the traditional one both free and associated ion electrostatic contributions are taken into account and therefore the revised version of ion association concept is correct for weak and strong regimes of ion association. It is shown that AMSA theory is more preferable for the description of thermodynamic properties while the modified version of the MSA-MAL theory is more useful for the description of electrical properties. The capabilities of the developed approaches are illustrated by the description of thermodynamic and transport properties of electrolyte solutions in weakly polar solvents. The proposed theory is applied to explain the anomalous properties of electrical double layer in a low temperature region and for the treatment of the effect of electrolyte on the rate of intramolecular electron transfer. The revised concept of ion association is also used to describe the concentration dependence of dielectric constant in electrolyte solutions. 

Comparative Molecular Field Analysis The basic idea of Comparative Molecular Field Analysis developed by R.D. Cramer et al. (Tripos CoMFA ) is that a suitable sampling of the steric and electrostatic field around a ligand molecule may provide all the information necessary for explaining its biological property in a 3D-QSAR. The steric and electrostatic contributions to the total interaction energy between the ligand and a chosen probe are calculated... 

These considerations lead to the conclusion that a rational approach to.problems of the adhesion of cells to solid surfaces can be developed from knowledge of the surface properties of both the substrate and the cell. Solid surface energies can be obtained by measurements of contact angles and use of Neumann s equation (Eq. 6), thus allowing calculations of free energy charges associated with adhesion. Zeta potentials and resultant electrostatic contributions to adhesion can also be obtained experimentally. This type of approach should provide insight into microbial adhesion problems in the marine and aquatic environments, disease and infection and in the industrial immobilization of whole cells. 

---