Interaction site type models

The models used in our own work[40, 47-51]are of the interaction site type, where the intermolecular interactions result from a sum over pairwise interactions among sites in each molecule. Typically, each atom of the system is associated with a short ranged potential consisting of a Lennard-Jones 6-12 form, describing molecular shape and dispersion effects, and separately a partial charge describing a contribution to the electrostatic interactions. Such models dominate the descriptions used successfully for systems as diverse as CO2 and biopolymers. 

The MC simulation has been used for analysis of the TDS for the interacting adspecies on the inhomogeneous surfaces [245-247]. Analysis [245,246] has been given to lattices with two types of sites and various patterns of their discrete and Gauss distributions relative to each other. The number of peaks during TDS splitting depends on both adspecies interactions and type of the surface inhomogeneity. The model has been applied to the CO/MgO TDS description to conclude that for this system the lateral interaction contribution is small. 

Capsule membrane PTC systems are more amenable to a mechanistic analysis than typical triphase systems where the mechanism of interaction between the aqueous and organic phases with the catalytic sites is complex and not understood. A mechanism for capsule membrane PTC involving mass transfer and smface reaction for both PTC and IPTC reactions has been developed by Yadav and Mehta(1993), Yadav and Mistry (1995). A Langmuir-Hinshelwood type model with the anchored quaternary-nucleophile complex as the active site was assumed to govern the overall rate of reaction... 

Another example of modeling the structure of this type of CSP is presented by Francotte and Wolf [47]. They prepared benzoylcellulose beads, in a pure polymeric form as a sorbent, for the chromatographic resolution of racemic compounds like benzylic alcohols and acetates of aliphatic alcohols and diols. Their experimental results implicated multiple interaction sites to be involved in the complexation. Rationalizing the interaction mechanism required a more systematic investigation of the factors influencing separations and, to address the structural features of the cellulose tribenzoate, they carried out molecular modeling with molecular mechanics. The key question being addressed is to what extent is the polysaccharide backbone exposed to small molecules when sterically encumbered benzoates are attached ... 

Water models can be conveniently divided into three types. In the simple interaction-site models each water molecule is maintained in a rigid geometry and the interaction between molecules is described using pairwise Coulombic and Lennard-Jones expressions. Flexible models permit internal changes in conformation of the molecule. Finally, models have been developed that explicitly include the effects of polarisation and many-body effects. 

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