Electrostatic energy correlation correction

For a better understanding of the nature of the adsorption forces between TNB and the siloxane surface of clay minerals, the decomposition scheme of Sokalski et al. [199] was applied. The results of such energy decomposition are presented in Table 6. They are in complete agreement with qualitative conclusions presented above. One may see that two dominant attractive contributions govern the adsorption of TNB. As it is expected, one is an electrostatic contribution, and the other one is contribution, which includes components that originate from the electronic correlation. The electronic correlation related contributions include the dispersion component and a correlation correction to electrostatic, exchange, and delocalization terms of the interaction energy. 

Moszynski R, Rybak S, Cybulski SM, Chalasinski G (1990) Correlation correction to the hartree-fock electrostatic energy including orbital relaxation. Chem Phys Lett 166 609-614... 

AE(2) e(20) cdisp AE Dispersion energy arising between SCF monomers (2nd order) Electrostatic-correlation energy (2nd order). Intra-monomer correlation correction to (22) 1. Deformation-intra-correlation. [e-nd r] 2. Deformation-dispersion. [e. jnd]... 

The previous components of the interaction energy can be derived in the independent particle approximation and so appear within the context of Hartree-Fock level calculations. Nevertheless, inclusion of instantaneous correlation will affect these properties. Taking the electrostatic interaction as an example, the magnimde of this term, when computed at the SCF level, will of course be dependent on the SCF electron distributions. The correlated density will be different in certain respects, accounting for a different correlated electrostatic energy. The difference between the latter two quantities can be denoted by the correlation correction to the electrostatic energy. 

The electron-electron repulsion contribution is often decomposed into classical electrostatic repulsion energy, plus corrections for the Pauli principle (exchange) and electron correlation... 

In spite of all the evolution, there are still important problems for the calculation of intermolecular energies. Hartree-Fock (HF) methods use one-electron orbitals and therefore cannot account for those phenomena that depend on the simultaneous behavior of several electrons. Thus, HF energies may correctly represent the kinetic energies of electrons and the electrostatic effects between electrons and nuclei, but cannot take into account electron correlation. The results obtained at the limit of a complete (i.e. infinitely rich) basis set are called HF-limit energies and wavefunctions, the ideal best that can be obtained with one-electron orbitals. This intrinsic limitation forbids the treatment of dispersion energy, a crucial part of the intermolecular potential (see Chapter 4). Thus, for example, HF methods are intrinsically unsuitable for the calculation of the lattice energies of organic crystals. 

MP correlation corrections are particularly important when determining binding energies of van der Waals molecules (see Intermolecular Interactions by Perturbation Theory). These are held together by electrostatic, induced, dispersion... 

The classical Thomas-Fermi theory is a statistical theory which allows the electrons to move independently of each other. The one-electron wavefunctions are obtained using the classical electrostatic potential only. Corrections to the simple theory are obtained by introducing an exchange and a correlation correction. Also a gradient correction has been introduced to correct for the use of a free-electron gas kinetic energy in the original theory [203, 204]. 

As with SCRF-PCM only macroscopic electrostatic contribntions to the Gibbs free energy of solvation are taken into account, short-range effects which are limited predominantly to the first solvation shell have to be considered by adding additional tenns. These correct for the neglect of effects caused by solnte-solvent electron correlation inclnding dispersion forces, hydrophobic interactions, dielectric saturation in the case of... 

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