Van der Waals interactions in rare-gas dimers: The role of interparticle interactions

TL;DR

This study explores how different interparticle interactions affect van der Waals forces in rare-gas dimers, revealing that long-range Coulomb tails preserve these interactions, while short-range interactions eliminate them, leading to purely repulsive potentials.

Contribution

It provides a detailed analysis of the impact of interaction range on van der Waals forces in rare-gas dimers using high-accuracy coupled-cluster calculations.

Findings

Long-range Coulomb interactions maintain van der Waals forces.

Short-range interactions lead to purely repulsive potential energy curves.

Different theoretical methods show consistent trends.

Abstract

We investigate the potential energy curves of rare-gas dimers with various ranges and strengths of interparticle interactions (nuclear-electron, electron-electron, and nuclear-nuclear interactions). Our investigation is based on the highly accurate coupled-cluster theory associated with those interparticle interactions. For comparison, the performance of the corresponding Hartree-Fock theory, second-order Moller-Plesset perturbation theory, and density functional theory is also investigated. Our results reveal that when the interparticle interactions retain the long-range Coulomb tails, the nature of van der Waals interactions in the rare-gas dimers remains similar. By contrast, when the interparticle interactions are sufficiently short-range, the conventional van der Waals interactions in the rare-gas dimers completely disappear, yielding purely repulsive potential energy curves.