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Local exchange‐correlation approximations and first‐row molecular dissociation energies
Author(s) -
Becke A. D.
Publication year - 1985
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.560270507
Subject(s) - diatomic molecule , dissociation (chemistry) , bond dissociation energy , atomic physics , bond length , chemistry , molecule , bond energy , correlation , physics , molecular physics , quantum mechanics , mathematics , geometry
Recent X α calculations of bond energies and other related properties of first‐row diatomic molecules show very encouraging agreement with experiment. In the worst cases, however, the X α dissociation energies overestimate the experimental values by almost 2 eV. Therefore, we have examined several refinements of the X α theory and their effects on molecular bond lengths, bond energies, and vibrational frequencies. Among them, gradient corrections to the X α exchange energy and also some variations of the local spin‐density correlation energy approximation are considered. We find that a local exchange‐correlation functional with gradient corrections gives dissociation energies in significantly better agreement with experiment than the X α approximation.