Breaking bonds with the state-selective multireference coupled-cluster method employing the single-reference formalism
- Department of Chemistry, University of Arizona, Tucson, Arizona 85721 (United States)
The state-selective (SS) multireference coupled-cluster (CC) method exploiting the single-reference (SR) formalism [P. Piecuch, N. Oliphant, and L. Adamowicz, J. Chem. Phys. [bold 99], 1875 (1993)] is applied to BH and H[sub 2]O at equilibrium and displaced geometries. Different selections of active spaces are considered. Comparison with the SR CC approaches involving single and double (CCSD), single, double, and triple (CCSDT) and single, double, triple, and quadruple (CCSDTQ) excitations, and with the full configuration interaction method, indicates remarkable stability and accuracy of the SS CC results for difficult bond breaking cases. For the first time, the [ital ab] [ital initio] SS CC calculations include the most complete SS CCSD(TQ) approximation, which emerges through selection of the most essential clusters appearing in the full SR CCSDTQ theory.
- DOE Contract Number:
- FG03-93ER61605
- OSTI ID:
- 6693219
- Journal Information:
- Journal of Chemical Physics; (United States), Journal Name: Journal of Chemical Physics; (United States) Vol. 102:2; ISSN JCPSA6; ISSN 0021-9606
- Country of Publication:
- United States
- Language:
- English
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State-selective multi-reference coupled-cluster theory employing the single-reference formalism: Application to an excited state of H[sub 8]
Related Subjects
74 ATOMIC AND MOLECULAR PHYSICS
ACCURACY
BORON COMPOUNDS
BORON HYDRIDES
CHEMICAL BONDS
COMPARATIVE EVALUATIONS
CONFIGURATION INTERACTION
EQUILIBRIUM
EVALUATION
GEOMETRY
HYDRIDES
HYDROGEN COMPOUNDS
MATHEMATICS
MULTIPOLES
OXYGEN COMPOUNDS
QUADRUPOLES
SYMMETRY BREAKING
WATER