Extrapolation of high-order correlation energies: the WMS model.
Phys Chem Chem Phys
; 20(43): 27375-27384, 2018 Nov 07.
Article
em En
| MEDLINE
| ID: mdl-30357169
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.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Tipo de estudo:
Prognostic_studies
Idioma:
En
Revista:
Phys Chem Chem Phys
Assunto da revista:
BIOFISICA
/
QUIMICA
Ano de publicação:
2018
Tipo de documento:
Article