Van der Waals forces in density functional theory: perturbational long-range electron interaction corrections

TL;DR

This paper introduces a new density functional approach that explicitly accounts for long-range van der Waals interactions by combining a range-separated hybrid functional with perturbational long-range correlation corrections, improving the description of weakly bound complexes.

Contribution

It proposes a novel range-separated hybrid functional with perturbational long-range correlation corrections for better van der Waals force modeling in density functional theory.

Findings

Enhanced accuracy in describing van der Waals complexes

Effective separation of short- and long-range electron interactions

Applicable to rare gas dimers and similar systems

Abstract

Long-range exchange and correlation effects, responsible for the failure of currently used approximate density functionals in describing van der Waals forces, are taken into account explicitly after a separation of the electron-electron interaction in the Hamiltonian into short- and long-range components. We propose a "range-separated hybrid" functional based on a local density approximation for the short-range exchange-correlation energy, combined with a long-range exact exchange energy. Long-range correlation effects are added by a second-order perturbational treatment. The resulting scheme is general and is particularly well-adapted to describe van der Waals complexes, like rare gas dimers.