It is shown that a recently proposed quadratic configuration interaction (QCI) method, when limited to single and double substitutions (QCISD), represents a special case of the single reference coupled cluster approach. When applied to higher levels of substitutions (QCISDT) the method ceases to be size extensive. The relationship of QCISD method with existing coupled cluster approaches is shown in detail.
No takes yet. Share an insight, caveat, or question.
Paldus et al. (1989) studied this question.
Synapse has enriched 5 closely related papers on similar clinical questions. Consider them for comparative context: