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Issue 43, 2018
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Extrapolation of high-order correlation energies: the WMS model

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We have developed a new composite model chemistry method called WMS (Wuhan–Minnesota scaling method) with three characteristics: (1) a composite scheme to approximate the complete configuration interaction valence energy with the affordability condition of requiring no calculation more expensive than CCSD(T)/jul-cc-pV(T+d)Z, (2) low-cost methods for the inner-shell correlation contribution and scalar relativistic correction, and (3) accuracy comparable to methods with post-CCSD(T) components. The new method is shown to be accurate for the W4-17 database of 200 atomization energies with an average mean unsigned error (averaged with equal weight over strongly correlated and weakly correlated subsets of the data) of 0.45 kcal mol−1, and the performance/cost ratio of these results compares very favorably to previously available methods. We also assess the WMS method against the DBH24-W4 database of diverse barrier heights and the energetics of the reactions of three strongly correlated Criegee intermediates with water. These results demonstrate that higher-order correlation contributions necessary to obtain high accuracy for molecular thermochemistry may be successfully extrapolated from the lower-order components of CCSD(T) calculations, and chemical accuracy can now be obtained for larger and more complex molecules and reactions.

Graphical abstract: Extrapolation of high-order correlation energies: the WMS model

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The article was received on 04 Aug 2018, accepted on 10 Oct 2018 and first published on 18 Oct 2018

Article type: Paper
DOI: 10.1039/C8CP04973D
Citation: Phys. Chem. Chem. Phys., 2018,20, 27375-27384

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    Extrapolation of high-order correlation energies: the WMS model

    Y. Zhao, L. Xia, X. Liao, Q. He, M. X. Zhao and D. G. Truhlar, Phys. Chem. Chem. Phys., 2018, 20, 27375
    DOI: 10.1039/C8CP04973D

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