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A posteriori corrections to multireference limited configuration interaction based on a Brillouin–Wigner perturbative analysis
Author(s) -
Hubac̆ I.,
Mach P.,
Wilson S.
Publication year - 2002
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.10288
Subject(s) - full configuration interaction , configuration interaction , multireference configuration interaction , perturbation theory (quantum mechanics) , a priori and a posteriori , coupled cluster , scaling , physics , quantum mechanics , excited state , molecule , mathematics , philosophy , geometry , epistemology
A new a posteriori correction to the method of limited configuration interaction is described that attempts to restore a linear scaling with particle number. The corrections are based on an analysis of the limited configuration interaction method in terms of the Brillouin–Wigner perturbation theory using a Lippmann–Schwinger‐like equation. The new correction procedure is general and, in this work, the application to the limited multireference configuration interaction approximation is considered in some detail. An illustrative application to the rigid rotation of the diimine molecule is presented and the results are compared with those obtained by employing Davidson‐like corrections and the corresponding full configuration interaction energies. © 2002 Wiley Periodicals, Inc. Int J Quantum Chem, 2002