Molecular applications of size-extensive quasi-Hilbert- and quasi-Fock-space coupled-cluster formalisms using incomplete model spaces

✍ Scribed by Debasis Mukhopadhyay Jr.; Debashis Mukherjee

• Publisher: Elsevier Science
• Year: 1991
• Tongue: English
• Weight: 553 KB
• Volume: 177
• Category: Article
• ISSN: 0009-2614
• DOI: 10.1016/0009-2614(91)85080-g

✦ Synopsis

In this paper, we report the first numerical applications of the size-extensive quasi-Hilbert-and quasi-Foek-space coupledcluster theories, developed by us recently, to the ground and the first excited '% states of the molecule LiH. Unlike the corresponding Fock-space theories, there is no need to solve for the cluster amplitudes of lower-valence model spaces characterizing LiH+ and LiH-species in these formulations. The results are compared with the CISD values, those from the Foek-space theories and the coupled-cluster-based linear-response theory, and are found to be quite satisfactory. This indicates the computational viability of the two formulations.