Triplet excitation energies in the coupled cluster singles and doubles model using an explicit triplet spin coupled excitation space

Kasper Hald
Department of Chemistry, Århus University, DK-8000 Århus C, Denmark

Christof Hättig
Forschungszentrum Karlsruhe, Institute of Nanotechnology, P.O. Box 3640, D-76021 Karlsruhe, Germany

Poul Jørgensen
Department of Chemistry, Århus University, DK-8000 Århus C, Denmark

J. Chem. Phys. 113, 7765-7772 (2001).
(Received 22 May 2000; accepted 17 August 2000)

Triplet excitation energies are calculated from the response eigenvalue equation for the coupled cluster singles and doubles (CCSD) model using an integral direct approach and an explicit spin coupled triplet excitation space. The cost of one linear transformation for the triplet excitation energy is about two times the cost of one linear transformation for the singlet excitation energy. The triplet excitation spectrum of benzene is calculated using from 147 to 432 basis functions. The calculated triplet excitation energies are compared with experimental and other theoretical values.

View Article PDF (access restricted to domain theochem.rub.de)

Back to the list of Publications by the Quantum Chemistry (Hättig) Group