Performance of one-body reduced density matrix functionals for the homogeneous electron gas

TL;DR

This paper evaluates various exchange-correlation-energy functionals within reduced density matrix functional theory for the homogeneous electron gas, demonstrating improved accuracy with recent approximations and modifications that reproduce exact correlation energies.

Contribution

The study introduces modifications to recent functionals that exactly reproduce the correlation energy of the homogeneous electron gas, enhancing their accuracy.

Findings

Recent functionals yield better correlation energies and momentum distributions.

Modified functionals reproduce the exact correlation energy of the homogeneous electron gas.

Improvements over previously known functionals are demonstrated.

Abstract

The subject of this study is the exchange-correlation-energy functional of reduced density matrix functional theory. Approximations of this functional are tested by applying them to the homogeneous electron gas. We find that two approximations recently proposed by Gritsenko, Pernal, and Baerends, J. Chem. Phys., {\bf 122}, 204102 (2005), yield considerably better correlation energies and momentum distributions than previously known functionals. We introduce modifications to these functionals which, by construction, reproduce the exact correlation energy of the homogeneous electron gas.