Hartree Fock interaction energy

A symmetry-adapted perturbation theory approach for the calculation of the Hartree-Fock interaction energies has been proposed by Jeziorska et al.105 for the helium dimer, and generalized to the many-electron case in Ref. (106). The authors of Refs. (105-106) developed a basis-set independent perturbation scheme to solve the Hartree-Fock equations for the dimer, and analyzed the Hartree-Fock interaction energy in terms of contributions related to many-electron SAPT reviewed in Section 7. Specifically, they proposed to replace the Hartree-Fock equations for the... 

Table 1-5. Comparison of low-order approximations (in Hartree) to the Hartree-Fock interaction energies of the He-C2H2, He-CO, and Ar-HF complexes. The expression (—N) denotes the factor 10 w...

Morokuma Partitioning of the Hartree-Fock Interaction Energy... 

In 1971 Morokuma258 proposed a simple partitioning of the Hartree-Fock interaction energy into some physically interpretable contributions, hopefully related to the components of the interaction energy as defined by SAPT. In this method one removes from the Fock matrix and from the energy expression the integrals (in the atomic basis) which are assumed to be unrelated to the considered type of... 

The essential problem with the partitioning of the Hartree-Fock interaction energy is related to the fact that the so-called Hartree-Fock deformation or delocalization energy,... 

Jeziorska M, Jeziorski B, Cizek J (1987) Direct calculation of the Hartree-Fock interaction energy via exchange-perturbation expansion. The He... He interaction. Int J Quantum Chem 32 149—164... 

Moszynski R, Heijmen TGA, Jeziorski B (1996) Symmetry-adapted perturbation theory for the calculation of Hartree-Fock interaction energies. Mol Phys 88 741—758... 

Gutowski M, Piela L (1988) Interpretation of the Hartree-Fock interaction energy between closed-shell systems. Mol Phys 64 337-355... 

Szczesniak et al. considered the factors leading to the degree of linearity of the H-bond in the water dimer and the pyramidalization of the proton acceptor oxygen. The dependence of the Hartree-Fock interaction energy was calculated as a function of both a and (3 (see earlier), as were the dispersion energy, and second-order Mpller-Plesset correlation... 

The simplest ab initio method used to study van der Waals molecules is the Hartree-Fock method. To the Hartree-Fock interaction energy one should add the dispersion energy, which ranges from some 20% of the dissociation energy for the water dimer to twice the van der Waals well depth for He2, and is thus not negligible. The combined method may be termed SCF + Disp. 

The SCF -f- Disp method is frequently applied since it is relatively cheap and thus allows the calculation of many points on the potential energy surface. A useful potential may be obtained by empirical adjustments to the potential. For example, a damping function may be adjusted using experimental data or various components of a fitted dispersion energy may be scaled to more reasonable values . The Hartree-Fock interaction energy may also be improved, by replacing its multipole and induction components by energies derived from multipoles obtained from better calculations (e.g. Cl) or experiment cf. Refs 78 and 104-107. While these procedures may yield reasonable potentials, we feel that the predictive power of the SCF -I- Disp approach is limited. 

Moszynski, R. (1996). Symmetry-Adapted Perturbation Theory for the Calculation of Hartree-Fock Interaction Energies, Mol Phys., 88,741-758. 

For the Li -H2 system, the Hartree-Fock interaction energy, which includes the effect of overlap forces, becomes comparable to that calculated from a perturbative treatment of the electrostatic (ion-quadrupole) and inductive (ion-induced-dipole) contributions when the interaction energy is O.l eV. In this case, however, the Langevin model may not even be used at thermal energies since the ion-quadrupole interaction energy is comparable to that due to the ion-induced-dipole interaction in the relevant range of separation ( SA). ... 

The Ar2 potential curve is shown in Fig. 21. Considering for the present only the attractive state, the Hartree-Fock interaction energy only becomes comparable to that of the polarization potential when the interaction energy is of the order of 0.1 eV. Once again, such considerations restrict the use of the Langevin model to thermal energies. Here, there is no possible ion-quadrupole contribution and in both these cases, dispersion forces are negligible. 

Figure 4 Structures and MP2/6-31G (0.25) interaction energies (kcal mol" ) for 10 stacked ba.se pairs. The structure has been optimized by the MP2-fitted empirical potential under the as.sumptions that the bases are coplanar and the vertical separation of bases is constant (3.3 or 3,4 A). The value.s in parentheses are the Hartree-Fock interaction energie,s...

The current applications of SAPT utilize usually a hybrid approach to compute the total interaction energy. As discussed in Section 6, the Hartree-Fock interaction energy contains the following SAPT corrections... 

One should mention that the Hartree-Fock interaction energy can be expanded rigorously in powers of The... 

There is no unequivocal operative definition of these terms allowing numerical computations. Consequently, many energy partition schemes have been proposed. Most are based on ideas presented first in 1971 by Morokuma [54, 55], who decomposed the variational Hartree-Fock interaction energy into AEes, AEpol, AEex and AEqt (note that this list does not include A disp, which must be calculated separately). DFT-calculated interaction energies have also been partitioned (see a review [56] on various classes of donor/acceptor complexes of transition metals and main group elements). 

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