Investigation of intermolecular interactions based on the atomic statistical model

Radzio‐Andzelm, Elżbieta

doi:10.1002/qua.560200303

Cited by 5 publications

(4 citation statements)

References 42 publications

(11 reference statements)

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“…One modification of the GK approach made by Radzio-Andzelm and Kolos − incorporated the exchange energy expression used in Jeziorski et al The total system density now included, in addition to the sum of the unperturbed system A and B densities (the basic GK assumption), three terms which accounted for electron exchange between the two systems. This modification significantly improved the results, especially for He 2 .…”

Section: Dft: Previous Attempts To Calculate Van Der Waals Forcesmentioning

confidence: 99%

Using Kohn−Sham Orbitals in Symmetry-Adapted Perturbation Theory to Investigate Intermolecular Interactions

2000

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This is the first reported use of a hybrid method involving density functional theory (DFT) and symmetry-adapted perturbation theory (SAPT) to calculate intermolecular interactions. This work was stimulated by the reported failures of supermolecular DFT calculations to adequately predict intermolecular (and interatomic) interactions, particularly of the van der Waals type. The goals are to develop a hybrid scheme that will calculate intermolecular interaction energies accurately and in a computationally efficient fashion, while including the benefits of the energy decomposition provided by SAPT. The computational savings result from replacing the costly perturbation theory treatment with DFT, which should include the intramolecular correlation effects on the intermolecular interaction energies. The accuracy of this new hybrid approach (labeled SAPT(DFT)) is evaluated by comparisons with higher level calculations. The test cases include He2, Ar2, Ar−H2, (H2O)2, (HF)2, CO2−CH3CN, and CO2-dimethylnitramine. The new approach shows mixed results concerning the accuracy of interaction energies. SAPT(DFT) correctly predicts all the qualitative trends in binding energies for all test cases. This is particularly encouraging in dimer systems dominated by dispersive interactions where supermolecular DFT fails to predict binding. In addition, the method achieves a drastic reduction (a factor of at least 100) in computational time over the higher level calculations often used to predict these forces. With respect to quantitative accuracy, this initial hybrid scheme, using the very popular exchange-correlation functional B3LYP, overestimates the second-order energy components (e.g., induction and dispersion terms) for all of the test cases, and subsequently overestimates the total interaction energy for all dimer systems except those heavily dominated by the electrotstatic interactions. The SAPT energy decomposition points to the use of DFT virtual orbital eigenvalues in the second-order perturbation terms as the likely cause for this error. These results are consistent with earlier work suggesting that DFT canonical virtual orbital energies obtained from commonly used functionals are less than optimal for use in such a perturbative scheme. The first-order interaction energy terms from the SAPT(DFT) are found to be generally more accurate than the second-order terms, and agree well with the benchmark values for dimers containing molecules with a permanent electric dipole moment. These first-order terms depend only upon the occupied MO eigenvectors, and hence are not affected by the inaccuracies in the Kohn−Sham DFT virtual orbital eigenvalues. These observations encourage future studies utilizing newly reported functionals, some of which have been developed to directly address problems with DFT virtual orbital energies and the asymptotic region of the electron density.

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Section: Dft: Previous Attempts To Calculate Van Der Waals Forcesmentioning

confidence: 99%

Using Kohn−Sham Orbitals in Symmetry-Adapted Perturbation Theory to Investigate Intermolecular Interactions

2000

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“…Waldman and Gordon (1979a,b) . Radzio-Andzelm (1981) has discussed ways for improving the Gordon-Kim approach throug:1 modifications of the kinetic and exchange terms. Waldman and Gordon (1979c) have generalized the Gordon-Kim approach and have used it for imestigating intermolecular interactions, in particular in the H 2 -He, H 2 -Ar and HCI-Ar systems.…”

Section: { L R Ud(5) (Re)/efo['mentioning

confidence: 99%

Energy Density Functional Theory of Many-Electron Systems

1990

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“…In the case of intermolecular interactions, further development of the statistical approach is related with introducing additional correction terms in formulas (2) for the kinetic, exchange, and correlation density functionals [ 11, [13][14][15][16][17][18][19][20][21]. However, in most of these developments, the main emphasis is directed to improving the form of E [p] in the frame of the zero-order perturbation treatment for the supermolecular density pAB(r), i.e., the supermolecular density still remains as a sum of the unperturbed oneelectron densities of the isolated subsystems A and B [22]: ( 5 ) where all the densities are assumed to be normalized to the corresponding number of electrons.…”

Section: E[(p(r)l = E K B ( R ) L + Eex[p(r)l + Ec[p(r)lmentioning

confidence: 99%

“…KoXos and Radzio [ 181 and Radzio-Andzelm [21] have, however, established the foundations for studying corrections to p A B ( r ) . Considering the He dimer as an example, KoXos and Radzio showed that the zero-order approximation for pAB(r) given by Eq.…”

Section: E[(p(r)l = E K B ( R ) L + Eex[p(r)l + Ec[p(r)lmentioning

confidence: 99%