On the Ground States of CaC and ZnC: A Multireference Brillouin-Wigner Coupled Cluster Study

0181561 - UFCH-W 20020195 RIV US eng J - Článek v odborném periodiku
Kerkines, I. S. K. - Pittner, Jiří - Čársky, Petr - Mavridis, A. - Hubač, I.
On the Ground States of CaC and ZnC: A Multireference Brillouin-Wigner Coupled Cluster Study.
Journal of Chemical Physics. Roč. 117, č. 21 (2002), s. 9733-9739. ISSN 0021-9606. E-ISSN 1089-7690
Grant CEP: GA MŠMT OC D23.001; GA AV ČR IAA4040108; GA ČR GA203/99/D009
Výzkumný záměr: CEZ:AV0Z4040901
Klíčová slova: CaC * ZnC * Brillouin-Wigner coupled cluster study
Kód oboru RIV: CF - Fyzikální chemie a teoretická chemie
Impakt faktor: 2.998, rok: 2002

We test the recently developed state-specific multireference Brillouin-Wigner coupled cluster (MRBWCCSD) method against the single reference CCSD method by examining theoretically the competing X3 .Sigma.- and 5.Sigma.- states of the isovalent calcium and zinc carbide diatomics level, CaC is "incorrectly" predicted to have a ground 5.Sigma.- state: however, the MRBWCCSD treatment restores the correct state ordering, and improves significantly the energetics for both molecules. Further comparison with various single- and multireference treatmens shows that the latter are absolutely necessary for obtaining meaningfil results for the ground states in both molecules.
Trvalý link: http://hdl.handle.net/11104/0078112