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Is combining meta‐GGA correlation functionals with the OPTX exchange functional useful?
Author(s) -
Proynov Emil I.,
Thakkar Ajit J.
Publication year - 2005
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.20758
Subject(s) - intramolecular force , intermolecular force , chemistry , hydrogen bond , density functional theory , computational chemistry , thermodynamics , molecule , chemical physics , physics , stereochemistry , organic chemistry
The recent generalized gradient approximation (GGA) density functional OCS1 of Handy and Cohen is implemented in the deMon code and tested on a carefully selected set of problems. OCS1 is found to be accurate for molecular atomization energies, transition metal–ligand bonds, and systems with intramolecular hydrogen bonds. However, OCS1 encounters problems for systems with intermolecular hydrogen bonds. It also tends to elongate bond lengths systematically, and sometimes significantly. The OPTX exchange is combined with three meta‐GGA correlation functionals, Lap3, τ1, and τ2, the latter reported for the first time. The new meta‐GGA scheme OPTX exchange plus τ2 correlation called Oτ2 yields improved molecular geometries, NMR shielding constants, and an improved barrier height for the H+H 2 reaction. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2006