Electrostatic interactions many-body forces

Recently, a new theoretical method of calculating potential energy and dipole/polarizability surfaces for van der Waals molecules based on symmetry-adapted perturbation theory (sapt) of intermolecular forces (12)— (15) has been developed (16)-(24). In this method, referred to as many-body symmetry-adapted perturbation theory, all physically important contributions to the potential and the interaction-induced properties, such as electrostatics, exchange, induction, and dispersion are identified and computed separately. By making a perturbation expansion in the intermolecular interaction as well as in the intramolecular electronic correlation, it is possible to sum the correlation contributions to the different physical... 

If the electrostatic interaction between two like-charged particles is attractive, we call the interaction inverted and if the interaction between oppositely charged particles is repulsive, we also call it inverted. Ionic force inversion is not a denial of Coulomb s law. If it exists, it must be a manifestation of many-body interactions. For example, if two like-charged polymers electrostatically attract each other, it can only be through the mediation of counterions and/or polarizable solvent molecules. Force inversion is a topic currently of widespread interest in polyelectrolyte physics (this volume, Chapter 5). We currently believe that inverted forces can arise through several distinct types of interactions, and it may not always be easy to pick... 

By and large, the concentrated aqueous suspensions of nanosilicas are relatively stable (Figure 1.91) due to many-body electrostatic interactions between particles and hydration forces. However, even the concentrated suspensions of nanosilicas are sensitive to the changes in the concentration... 

On the other hand, a proper theoretical interpretation of experimental results for ajhe < 5 would require a true three-dimensional modeling of particle deposition process with appropriate expressions for the many-body electrostatic interactions. An attempt in this direction was undertaken by Oberholzer et al. [196], who considered the true three-dimensional transport in a force field stemming fi om adsorbed particles and the interface. Because the authors still used the LSA approach (generaUzed for the two particle/interface configuration as previously mentioned), the deviation fi om the two-dimensional RSA simulations with respect to was found to be not too significant. 

Simple potentials based on equation (2) have been used to describe the interaction of adsorbed hydrocarbon molecules with zeolites see, for example, Kiselev et al. For all-silica zeolites the electrostatic interaction is frequently neglected in such simulations. Further simplification is achieved when the two-body terms are calculated for whole CH groups instead of for individual atoms. Many of these applications assume that both the zeolite and the molecules are rigid. Some allow at least for torsions about C-C bonds in saturated hydrocarbons. More advanced approaches combine the intermolecular potentials with some type of force fields for the adsorbed organic molecules and/or for the zeolite framework. ... 

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