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Assessing How Correlated Molecular Orbital Calculations Can Perform versus Kohn–Sham DFT: Barrier Heights/Isomerizations
Author(s) -
Varandas António J. C.,
Martínez González Marco,
MonteroCabrera Luis A.,
Garcia de la Vega José M.
Publication year - 2017
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201700928
Subject(s) - basis set , isomerization , molecular orbital , chemistry , density functional theory , computational chemistry , limit (mathematics) , set (abstract data type) , basis (linear algebra) , molecule , computer science , mathematics , mathematical analysis , biochemistry , geometry , organic chemistry , programming language , catalysis
To assess the title issue, 38 hydrogen transfer barrier heights and 38 non‐hydrogen transfer barrier heights/isomerizations extracted from extensive databases have been considered, in addition to 4 2 p‐isomerization reactions and 6 others for large organic molecules. All Kohn–Sham DFT calculations have employed the popular M06‐2X functional, whereas the correlated molecular orbital (MO)‐based ones are from single‐reference MP2 and CCSD(T) methods. They have all utilized the same basis sets, with raw MO energies subsequently extrapolated to the complete basis set limit without additional cost. MP2 calculations are found to be as cost‐effective as DFT ones and often slightly more, while showing a satisfactory accuracy when compared with the reference data. Although the focus is on barrier heights, the results may bear broader implications, in that one may see successes and difficulties of DFT when compared with traditional MO theories for the same data.