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Benchmarking the performance of spin-component scaled CC2 in ground and electronically excited states.
- Source :
-
Physical chemistry chemical physics : PCCP [Phys Chem Chem Phys] 2008 Jul 28; Vol. 10 (28), pp. 4119-27. Date of Electronic Publication: 2008 Jun 05. - Publication Year :
- 2008
-
Abstract
- A generalization of the spin-component scaling and scaled opposite-spin modifications of second-order Møller-Plesset perturbation theory to the approximate coupled-cluster singles-and-doubles model CC2 (termed SCS-CC2 and SOS-CC2) is discussed and a preliminary implementation of ground and excited state energies and analytic gradients is reported. The computational results for bond distances, harmonic frequencies, adiabatic and 0-0 excitation energies are compared with experimental results to benchmark their performance. It is found that both variants of the spin-scaling increase the robustness of CC2 against strong correlation effects and lead for this method even to somewhat larger improvements than those observed for second-order Møller-Plesset perturbation theory. The spin-component scaling also enhances systematically the accuracy of CC2 for 0-0 excitation energies for pi --> pi* and n --> pi* transitions, if geometries are determined at the same level.
Details
- Language :
- English
- ISSN :
- 1463-9076
- Volume :
- 10
- Issue :
- 28
- Database :
- MEDLINE
- Journal :
- Physical chemistry chemical physics : PCCP
- Publication Type :
- Academic Journal
- Accession number :
- 18612515
- Full Text :
- https://doi.org/10.1039/b803727b