Separation of dynamic and nondynamic correlation
Abstract
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.
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BibTeX
@article{ramoscordoba2026separation,
title = {{Separation of dynamic and nondynamic correlation}},
author = {Eloy Ramos-Cordoba and Pedro Salvador and Eduard Matito},
journal = {Physical Chemistry Chemical Physics},
year = {2026},
month = oct,
doi = {10.1039/c6cp03072f},
eprint = {1608.04266},
archivePrefix = {arXiv},
url = {https://hal.science/hal-05786183v1},
note = {CC BY},
}
RIS
TY - JOUR
TI - Separation of dynamic and nondynamic correlation
AU - Eloy Ramos-Cordoba
AU - Pedro Salvador
AU - Eduard Matito
PY - 2026
DA - 2026/10/08
JO - Physical Chemistry Chemical Physics
DO - 10.1039/c6cp03072f
UR - https://hal.science/hal-05786183v1
AB - 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.
SN - 1463-9076
SN - 1463-9084
ER -