Embedded cluster density approximation for systems with nonlocal electron correlation
• Chen Huang
Chen Huang
Florida State University
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## Abstract

Local correlation methods rely on the assumption that electronic correlation is nearsighted. In this work, we develop a method to alleviate this assumption. The first step is to approximately decompose the electron correlation to the nearsighted and farsighted components based on the wavelength decomposition of electron correlation by Langreth and Perdew. The nearsighted component is then calculated using the recently developed embedded cluster density approximation (ECDA) which is a local correlation method formulated in the context of density functional theory. The farsighted component is calculated based on the system’s Kohn-Sham orbitals. The accuracy of this new method depends on the quality of the decomposition. We examined the method’s accuracy by patching the random phase approximation (RPA) correlation energy in a H$${}_{24}$$ chain in which the electron correlation is highly nonlocal. This new method predicts bond stretching energies, RPA correlation potential, and Kohn-Sham eigenvalues in good agreement with the benchmarks. Our results demonstrate the importance of including the farsighted part of electron correlation for studying systems having nonlocal correlations.

#### Peer review status:ACCEPTED

12 Dec 2019Submitted to International Journal of Quantum Chemistry
12 Dec 2019Submission Checks Completed
12 Dec 2019Assigned to Editor
17 Dec 2019Reviewer(s) Assigned
28 Jan 2020Review(s) Completed, Editorial Evaluation Pending
29 Jan 2020Editorial Decision: Revise Major