English

Capturing static and dynamic correlation with $\Delta \text{NO}$-MP2 and $\Delta \text{NO}$-CCSD

Chemical Physics 2020-06-05 v2 Strongly Correlated Electrons Computational Physics

Abstract

The ΔNO\Delta \text{NO} method for static correlation is combined with second-order M{\o}ller-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 (exFCI), and on par with conventional multireference approaches.

Keywords

Cite

@article{arxiv.1908.09914,
  title  = {Capturing static and dynamic correlation with $\Delta \text{NO}$-MP2 and $\Delta \text{NO}$-CCSD},
  author = {Joshua W. Hollett and Pierre-François Loos},
  journal= {arXiv preprint arXiv:1908.09914},
  year   = {2020}
}

Comments

29 pages, 7 figures

R2 v1 2026-06-23T10:57:23.154Z