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Density-functional theory-symmetry-adapted intermolecular perturbation theory with density fitting: a new efficient
A Hesselmann1, G Jansen, M Schütz
1Theoretische Organische Chemie, Institut für Organische Chemie, Universität Duisburg-Essen, Campus Essen, Universitätsstrasse 5, D-45117 Essen, Germany. andreas@theochem.uni-duesseldorf.de
The Journal of Chemical Physics
|January 11, 2005
Summary
A new computational method, density fitting DFT-SAPT, significantly reduces the cost of calculating intermolecular interactions. This accurate approach outperforms traditional methods for systems like the benzene dimer.
Area of Science:
- Computational Chemistry
- Quantum Chemistry
- Theoretical Chemistry
Background:
- Symmetry-adapted perturbation theory (SAPT) combined with density-functional theory (DFT) is a powerful tool for studying intermolecular interactions.
- Conventional DFT-SAPT methods face computational cost limitations, especially for larger systems and basis sets.
Purpose of the Study:
- To implement and evaluate a density-fitted version of the DFT-SAPT approach (DF-DFT-SAPT).
- To assess the accuracy and computational efficiency of DF-DFT-SAPT compared to existing methods.
Main Methods:
- Density fitting of two-electron integrals was applied to the DFT-SAPT method.
- The accuracy was tested on the ethyne dimer using suitable auxiliary basis sets.
- The method was applied to analyze three configurations of the benzene dimer.
Main Results:
- DF-DFT-SAPT shows a drastically reduced computational cost, scaling as the fifth power of molecular size.
- Errors introduced by density fitting are minimal (<10^-3 kcal/mol), significantly smaller than basis set errors.
- DF-DFT-SAPT performance exceeds that of second-order Møller-Plesset perturbation theory (MP2) for the benzene dimer.
Conclusions:
- DF-DFT-SAPT provides a computationally efficient and accurate method for calculating intermolecular interaction energies.
- The method's accuracy is comparable to high-level theoretical estimates, making it a valuable tool for theoretical chemistry research.