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SVECV-F12: A Composite Scheme for an Accurate and Cost Effective Evaluation of Reaction Barriers. I. Benchmarking Using the HTBH38/08 and NHTBH38/08 Barrier Heights Databases

preprint
submitted on 30.01.2020 and posted on 31.01.2020 by Oscar Ventura
A simple version of a composite scheme is described, based on a combination of density functional geometry and frequencies evaluation, valence energies obtained using the CCSD(T)-f12 method extrapolated to the complete basis set limit, and core-valence correlation corrections employing the MP2 method. The procedure was applied to the 38 reactions in Truhlar’s HTBH38/08 and NHTBH38/08 databases. Mean unsigned deviation (MUD) for the complete set of 68 independent barriers is 0.43 kcal mol-1, compared to 1.37 kcal/mol for G4 and 1.69 kcal/mol for the dispersioncorrected M06-2X method. Its accuracy is also better that that of other calculations using composite methods of similar cost. The MUD of the new scheme on the barriers in the DBH24/08 subset (12 out of the 38 reactions in both other sets) is 0.31 kcal mol-1, better than that obtained at the expensive CCSD(T,full)/aug-cc-pCV(T+d)Z level (0.46 kcal mol-1) and comparable to the most exact (and costly) Wn calculations (MUD=0.14 kcal mol-1). The maximum unsigned deviation (MaxUD) of the new method for all the reactions studied is 1.71 kcal/mol. G4 and M06-2X, on the other side, exhibit MaxUDs of 6.7 and 8.4 kcal/mol respectively

Funding

ANII

PEDECIBA

Alexander von Humboldt-Stiftung

History

Email Address of Submitting Author

oscar.n.ventura@gmail.com

Institution

CCBG-DETEMA, Universidad de la República, Uruguay

Country

Uruguay

ORCID For Submitting Author

0000-0001-5474-0061

Declaration of Conflict of Interest

No conflict of interest

Version Notes

Version 1.0

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