Intramolecular correlations, self-consistent

These surfaces are all based on some combination of ab initio electronic structure calculations plus fitting. The AD and BM surfaces are based respectively in whole or in part on extended-basis-set single-configuration self-consistent-field calculations, whereas the RB and RBST calculations are based on calculations including electron correlation by Moller-Plesset fourth-order perturbation theory. For the rigid-rotator calculations R., the intramolecular internuclear distances R- and R ... 

Chipot C, Rinaldi D, Rivail JL (1992) Intramolecular electron correlation in die self-consistent reaction field model of solvation. A MP2/6-31G ab initio study of the NH3—HC1 complex. Chem Phys Lett 191 287- 292... 

C. Chipot, D. Rinaldi, and J.-L. Rivail, Chem. Phys. Lett., 191, 287 (1992). Intramolecular Electron Correlation m the Self-Consistent Reaction Field Model of Solvation. A MP2/6-31G Ab Initio Study of the NH,-HC1 Complex. 

Finally, we mention that very recently three other integral equation approaches to treating polymer systems have been proposed. Chiew [104] has used the particle-particle perspective to develop theories of the intermolecular structure and thermodynamics of short chain fluids and mixtures. Lipson [105] has employed the Born-Green-Yvon (BGY) integral equation approach with the Kirkwood superposition approximation to treat compressible fluids and blends. Initial work with the BGY-based theory has considered lattice models and only thermodynamics, but in principle this approach can be applied to compute structural properties and treat continuum fluid models. Most recently, Gan and Eu employed a Kirkwood hierarchy approximation to construct a self-consistent integral equation theory of intramolecular and intermolecular correlations [106]. There are many differences between these integral equation approaches and PRISM theory which will be discussed in a future review [107]. 

The above physical features imply that a fully self-consistent treatment of intramolecular and intermolecular pair correlations is more important for star polymers than linear chains, and the concept of ideality is expected to be of much less utility even at high melt densities. The treatment of star polymers within a self-consistent PRISM formalism has been very recently pursued by Grayce and Schweizer. Here we give a brief description of some of the essential theoretical modifications... 

Intramolecular correlations are handled in different approximate manners in the various BGY approaches. Taylor and Lipson treat pair correlations on the same chain as input to the theory in a manner similar to PRISM theory. In contrast, the formulations of Eu and Gan, " and also Attard, yield closed integral equations for both the intra- and intermolecular pair distribution functions. Thus, in a sense the intra- and intermolecular pair correlations are treated on an equal footing, and a self-consistent integral equation theory is naturally obtained. Eu and Gan have recently presented a comparison between their BGY approach and self-consistent and non-self-consistent PRISM theory, in both general conceptual terms and within the context of numerical predictions for specific model hard-core systems. For the jointed hardcore chain model studies, the theory of Eu and Gan appears quantitatively superior to PRISM predictions, particularly for the equation of state. ... 

The question of the effects of attractive tail potentials on macro-molecular structure, and the appropriate closure(s), require much further study. Advances in the closure question may also result in more thermodynamically consistent theories, which is important for questions such as the equation of state, excess properties of multicomponent systems, and construction of constant pressure (not volume) theories. Other basic theoretical issues relate to the potential importance of corrections to site preaveraging, and the development of tractable schemes to systematically compute such corrections. The issue of self-consistency of intramolecular and intermolecular correlations is rather unsettled from the point of view of both how important these effects are (the answer is problem-specific), and how to best go about construeting a computationally convenient theory to treat them. 

Neglecting on the first step the correlations between adsorbed molecules we shall describe the relaxation processes by one-pm ticle distribution function fc(E,r,t) of molecules of chemical sort c with energy E at point r. The adsorbed molecule is deemed to be in the static potential field (r, C) (where is the vector of intramolecular coordinates), that includes both static surface potential and the self-consistent potential of interaction between molecules. Each molecule interacts with the phonon and electron subsystems of solid body (inelastic and non-adiabatic interactions respectively) uid collides with other adsorbed molecules. Thus from the... 

The standard approximation for the tJi k) has been to invoke the Flory ideality hypothesis. Although this is not on as firm a footing as in the melt case, it is a good first approximation, and is useful because the self-consistent determination of intramolecular and intermolecular correlations is a demanding task in polymer blends. The monomer structure is input to the theory through the single chain structure factors, something which is difficult to do in other liquid state theories. 

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