The coupled-cluster method with full inclusion of single, double and triple excitations applied to high sectors of the Fock space

✍ Scribed by S.R. Hughes; Uzi Kaldor

• Publisher: Elsevier Science
• Year: 1993
• Tongue: English
• Weight: 370 KB
• Volume: 204
• Category: Article
• ISSN: 0009-2614
• DOI: 10.1016/0009-2614(93)90019-w

✦ Synopsis

The coupled-cluster method with singte, double and triple excitations (CCSDT or SUB3) is applied to a system with up to six electrons outside a closed shell. The Ne atom and its ions serve as a test case. Starting from Ne*+, electrons are added one at a time ah the way to Ne. Ionization potentials and excitation energies in the 2p shell are calculated. CCSDT gives good results for all sectors, with an average absolute error of 0.11 eV, whereas methods including triple excitations approximately or not at all fai for the higher sectors.