Extending the random-phase approximation for electronic correlation energies: The renormalized adiabatic local density approximation

TL;DR

This paper enhances the RPA method for electronic correlation energies by incorporating a renormalized ALDA kernel, leading to more accurate correlation and atomization energies in molecules and solids.

Contribution

It introduces a parameter-free renormalized ALDA kernel to improve RPA calculations of correlation energies, addressing systematic underestimations.

Findings

Improved correlation energies for small molecules.

Enhanced atomization energy predictions.

Effective for homogeneous electron gas.

Abstract

The adiabatic connection fluctuation-dissipation theorem with the random phase approximation (RPA) has recently been applied with success to obtain correlation energies of a variety of chemical and solid state systems. The main merit of this approach is the improved description of dispersive forces while chemical bond strengths and absolute correlation energies are systematically underestimated. In this work we extend the RPA by including a parameter-free renormalized version of the adiabatic local density (ALDA) exchange-correlation kernel. The renormalization consists of a (local) truncation of the ALDA kernel for wave vectors $q>2k_F$, which is found to yield excellent results for the homogeneous electron gas. In addition, the kernel significantly improves both the absolute correlation energies and atomization energies of small molecules over RPA and ALDA. The renormalization can be straightforwardly applied to other adiabatic local kernels.