K. Kowalski et P. Piecuch, A comparison of the renormalized and active-space coupled-cluster methods:Potential energy curves of BH and F-2, CHEM P LETT, 344(1-2), 2001, pp. 165-175
The renormalized noniterative CCSD(T) and CCSD(TQ) methods, which are the e
xamples of the method of moments of coupled-cluster (CC) equations, and the
active-space CC approach with internal and semi-internal triexcited cluste
rs (CCSDt) are applied to the potential energy curves of BH and F-2. It is
shown that the renormalized CCSD(T) and CCSD(TQ) methods are practically as
effective in removing the failing of the standard noniterative CC approach
es at larger internuclear separations as the CCSDt method. The results of t
he CCSDt and renormalized CCSD(T) and CCSD(TQ) calculations are also compar
ed with those obtained with other perturbative CC approaches that focus on
bond breaking. (C) 2001 Elsevier Science B.V. All rights reserved.