Extrapolation of high-order correlation energies: the WMS model. Issue 43 (24th October 2018)

• Record Type: Journal Article
• Authors: Zhao, Yan; Xia, Lixue; Liao, Xiaobin; He, Qiu; Zhao, Maria X.; Truhlar, Donald G.
• Is Part Of: Physical chemistry chemical physics. Volume 20:Issue 43(2018)
• Page Start: 27375
• Page End: 27384
• Publication Date: 2018-10-24
• Subjects: Chemistry, Physical and theoretical -- Periodicals; 541.3
• DOI: 10.1039/c8cp04973d
• Languages: English
• ISSNs: 1463-9076

Abstract

Abstract : We present a composite model chemistry, Wuhan–Minnesota scaled (WMS), with an excellent performance-to-cost ratio, including strongly correlated systems. Abstract : 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.