Electrostatic interactions energy decomposition

In a recent paper. Mo and Gao [5] used a sophisticated computational method [block-localized wave function energy decomposition (BLW-ED)] to decompose the total interaction energy between two prototypical ionic systems, acetate and meth-ylammonium ions, and water into permanent electrostatic (including Pauli exclusion), electronic polarization and charge-transfer contributions. Furthermore, the use of quantum mechanics also enabled them to account for the charge flow between the species involved in the interaction. Their calculations (Table 12.2) demonstrated that the permanent electrostatic interaction energy dominates solute-solvent interactions, as expected in the presence of ion species (76.1 and 84.6% for acetate and methylammonium ions, respectively) and showed the active involvement of solvent molecules in the interaction, even with a small but evident flow of electrons (Eig. 12.3). Evidently, by changing the solvent, different results could be obtained. 

Cumpaiu.on the accuracy of first order electrostatic and exchange terms obtained within various SCF interaction energy decompositions with corresponding SAPT results for the benchmark test case He..He (R--5.6 au). All interaction energy values are given in nH and corresponding errors are calculated in respect to SAPT results (in parentheses). 

Multiple M=P bonding in (OC)5M=PR becomes evident with ADF s bond energy analysis in terms of electrostatic interactions, Pauli repulsion, and orbital interactions from which the a,Ti-separation is obtained using a symmetry decomposition scheme [21]. For singlet (OC)5Cr=PR, which has a BDEst of 40.5 kcal/mol, the a- and n-components are 62.4 and 40.9 kcal/mol, respectively. 

The result of an energy decomposition analysis performed for this complex was also unusual. In contrast to numerous dihydrogen-bonded systems with significant predominance of the electrostatic interaction, the dihydrogen-bonded dimer (LiH H20)2 has shown the charge transfer contribution to exceed the electrostatic energy —125.30 versus —81.40 kcal/mol, respectively. 

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. 

As one can easily note, a well-defined hierarchy of successive interaction energy approximations, varying from the most expensive MP2 method to the various electrostatic energy representation (the more simplified the theory, the less computationally demanding calculation), demonstrates the utility of this decomposition scheme (Figure 8-3) ... 

Morokuma, K. Kitaura, K. Energy Decomposition Analysis of Molecular Interactions in Chemical Applications of Atomic and Molecular Electrostatic Potentials, Politzer, P Ed. Plenum New York, 1981, pp. 215-242. 

Among the non-local criteria, the possible role of the long range electrostatic interactions was recognized quite early on. On the basis of a simple energy decomposition scheme, where the OH bond energy is considered as the sum... 

Most recently, Glendening and Streitwicser have decomposed the interaction energy of the water dimer using natural bond orbitals. Their natural energy decomposition analysis (NEDA) combines the normal electrostatic and exchange energies into a single ES term,... 

The decomposition of the interaction energy of a molecule in the liquid, allowed by the nature of the NEMO potentials, shows a larger contribution of the polarization term with respect to the electrostatic one, compared to the dimer case. Diffusion coefficient, 2.3-10 cm /s, is in a good accord with experiment, but Tp and Xnmr are larger than experimental and also than the corresponding data calculated with the SPC model. 

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