Correction for dispersion and Coulombic interactions in molecular clusters with density functional derived methods

Research output: Contribution to journalResearch articleContributedpeer-review

Contributors

  • Mathias Rapacioli - , Universite Toulouse III - Paul Sabatier (Author)
  • Fernand Spiegelman - , Universite Toulouse III - Paul Sabatier (Author)
  • Dahbia Talbi - , Université Paul-Valéry Montpellier III (Author)
  • Tzonka Mineva - , École nationale supérieure de chimie de Montpellier (Author)
  • Annick Goursot - , École nationale supérieure de chimie de Montpellier (Author)
  • Thomas Heine - , Jacobs University (Author)
  • Gotthard Seifert - , Chair of Theoretical Chemistry (Author)

Abstract

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.

Details

Original languageEnglish
Article number244304
JournalJournal of Chemical Physics
Volume130
Issue number24
Publication statusPublished - 2009
Peer-reviewedYes

External IDs

Scopus 67650472796

Keywords

Keywords

  • DER-WAALS COMPLEXES, SMALL BENZENE CLUSTERS, POTENTIAL-ENERGY SURFACE, PARTIAL ATOMIC CHARGES, TIGHT-BINDING METHOD, SCC-DFTB METHOD, AB-INITIO, IV CHARGE MODEL, PI-PI INTERACTIONS, INTERMOLECULAR INTERACTIONS