Capturing static and dynamic correlation with ΔNO-MP2 and ΔNO-CCSD

The ΔNO method for static correlation is combined with second-order Møller-Plesset perturbation theory (MP2) and coupled-cluster singles and doubles (CCSD) to account for dynamic correlation. The MP2 and CCSD expressions are adapted from finite-temperature CCSD, which includes orbital occupancies an...

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Bibliographic Details
Published in:The Journal of chemical physics 2020-01, Vol.152 (1), p.014101-014101
Main Authors: Hollett, Joshua W., Loos, Pierre-François
Format: Article
Language:English
Subjects:
Configuration interaction
Correlation
Damping
Perturbation theory
Potential energy
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Summary:The ΔNO method for static correlation is combined with second-order Møller-Plesset perturbation theory (MP2) and coupled-cluster singles and doubles (CCSD) to account for dynamic correlation. The MP2 and CCSD expressions are adapted from finite-temperature CCSD, which includes orbital occupancies and vacancies, and expanded orbital summations. Correlation is partitioned with the aid of damping factors incorporated into the MP2 and CCSD residual equations. Potential energy curves for a selection of diatomics are in good agreement with extrapolated full configuration interaction results and on par with conventional multireference approaches.
ISSN:0021-9606
1089-7690
DOI:10.1063/1.5140669