Heßelmann, Andreas:
DFT-SAPT with density fitting: a new efficient method to study intermolecular interaction energies
2005
In: Journal of Chemical Physics, Band 122 (2005), S. 014103-1 - 014103-17
Artikel/Aufsatz in Zeitschrift / Fach: Chemie
Titel:
DFT-SAPT with density fitting: a new efficient method to study intermolecular interaction energies
Autor(in):
Heßelmann, Andreas
Erscheinungsjahr
2005
Erschienen in:
Journal of Chemical Physics, Band 122 (2005), S. 014103-1 - 014103-17

Abstract:

The previously developed DFT-SAPT approach, which combines symmetry-adapted intermolecular perturbation theory (SAPT) with a density-functional theory (DFT) representation of the monomers, has been implemented by using density fitting of two-electron objects. This new approach, termed DF-DFT-SAPT, scales with the fifth power of the molecular size and with the third power upon increase of the basis set size for a given dimer, thus drastically reducing the cost of the conventional DFT-SAPT method. The accuracy of the density fitting approximation has been tested for the ethyne dimer. It has been found that the errors in the interaction energies due to density fitting are below 10$^{-3}$ kcal/mol with suitable auxiliary basis sets and thus one or two orders of magnitude smaller than the errors due to the use of a limited atomic orbital basis set. An investigation of three prominent structures of the benzene dimer, namely the T-shaped, parallel displaced and sandwich geometries, employing basis sets of up to augmented quadruple-zeta quality shows that DF-DFT-SAPT outperforms second-order Moller-Plesset theory (MP2) and gives total interaction energies which are close to the best estimates infered from combining the results of MP2 and coupled-cluster theory with single, double, and perturbative triple excitations (CCSD(T)).

Abstract:

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