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Article Dans Une Revue Journal of Chemical Physics Année : 2009

Correction for dispersion and coulombic interactions in molecular clusters with density-functional derived methods : Application to polycyclic aromatic hydrocarbon

Résumé

The density functional based tight binding (DFTB) is a semiempirical method derived from the density functional theory (DFT). It inherits therefore its problems in treating van der Waals clusters. A major error comes from dispersion forces, which are poorly described by commonly used DFT functionals, but which can be accounted for by an a posteriori treatment DFT-D. This correction is used for DFTB. The self-consistent charge (SCC) DFTB is built on Mulliken charges which are known to give a poor representation of Coulombic intermolecular potential. We propose to calculate this potential using the class IV/charge model 3 definition of atomic charges. The self-consistent calculation of these charges is introduced in the SCC procedure and corresponding nuclear forces are derived. Benzene dimer is then studied as a benchmark system with this corrected DFTB (c-DFTB-D) method, but also, for comparison, with the DFT-D. Both methods give similar results and are in agreement with references calculations (CCSD(T) and symmetry adapted perturbation theory) calculations. As a first application, pyrene dimer is studied with the c-DFTB-D and DFT-D methods. For coronene clusters, only the c-DFTB-D approach is used, which finds the sandwich configurations to be more stable than the T-shaped ones.
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Dates et versions

hal-00418594 , version 1 (21-09-2009)

Identifiants

Citer

Mathias Rapacioli, Fernand Spiegelman, Dahbia Talbi, Tzonka Mineva, Annick Goursot, et al.. Correction for dispersion and coulombic interactions in molecular clusters with density-functional derived methods : Application to polycyclic aromatic hydrocarbon. Journal of Chemical Physics, 2009, 130 (24), pp.244304-10. ⟨10.1063/1.3152882⟩. ⟨hal-00418594⟩
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