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The significance of double substitutions in well‐correlated electronic wave functions
Author(s) -
Jasien Paul G.,
Dykstra Clifford E.
Publication year - 2009
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/qua.560240833
Subject(s) - weighting , dipole , wave function , coupled cluster , moment (physics) , chemistry , cluster (spacecraft) , function (biology) , computational chemistry , molecular physics , physics , configuration interaction , atomic physics , quantum mechanics , molecule , computer science , evolutionary biology , acoustics , biology , programming language
Abstract The enhancement of the weighting of double substitutions in correlated wave functions is a very significant effect from including into a wave function the higher‐level substitutions. The coupled cluster model seems quite effective at bringing about this enhancement and because of this it yields correlation energies in line with those obtained by variational configuration interaction explicitly involving higher‐level substitutions. The enhancement of double substitutions as a prominent higher‐order effect is demonstrated by calculations of the HF dipole moment curve, where this enhancement provides an important adjustment to the curve.