Issue 34, 2016

Separation of dynamic and nondynamic correlation


The account of electron correlation and its efficient separation into dynamic and nondynamic parts plays a key role in the development of computational methods. In this paper we suggest a physically-sound matrix formulation to split electron correlation into dynamic and nondynamic parts using the two-particle cumulant matrix and a measure of the deviation from idempotency of the first-order density matrix. These matrices are applied to a two-electron model, giving rise to a simplified electron correlation index that (i) depends only on natural orbitals and their occupancies, (ii) can be straightforwardly decomposed into orbital contributions and (iii) splits into dynamic and nondynamic correlation parts that (iv) admit a local version. These expressions are shown to account for dynamic and nondynamic correlation in a variety of systems containing different electron correlation regimes, thus providing the first separation of dynamic and nondynamic correlation using solely natural orbital occupancies.

Graphical abstract: Separation of dynamic and nondynamic correlation

Article information

Article type
06 May 2016
18 Jul 2016
First published
29 Jul 2016
This article is Open Access
Creative Commons BY license

Phys. Chem. Chem. Phys., 2016,18, 24015-24023

Author version available

Separation of dynamic and nondynamic correlation

E. Ramos-Cordoba, P. Salvador and E. Matito, Phys. Chem. Chem. Phys., 2016, 18, 24015 DOI: 10.1039/C6CP03072F

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