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A combined density functional and configuration interaction method
Author(s) -
Savin A.
Publication year - 1988
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.560340811
Subject(s) - atomic orbital , configuration interaction , configuration space , density functional theory , bond dissociation energy , correlation , spin density , dissociation (chemistry) , space (punctuation) , electronic correlation , series (stratigraphy) , chemistry , atomic physics , physics , computational chemistry , molecular physics , statistical physics , quantum mechanics , mathematics , molecule , condensed matter physics , geometry , computer science , paleontology , biology , operating system , electron
Abstract Correlation energies are divided into two parts. One contribution is given by a configuration interaction calculation in the space of the natural orbitals with occupation numbers larger than an arbitrary threshold v . The remaining part is obtained from a v ‐dependent functional of the electronic density. Representative examples (for which the existing spin‐density functionals fail) are (1) the correlation energies in the He and Be series and (2) the contribution of the correlation energy to the dissociation energy of the first‐row dimers. It is shown that even for large values of v the errors remain on the order of 0.01 hartree.