Noncovalent interactions from models for the M{\o}ller-Plesset adiabatic connection

TL;DR

This paper introduces models based on the M{4}ller-Plesset adiabatic connection to accurately simulate non-covalent interactions, reducing errors and outperforming existing methods without needing dispersion corrections.

Contribution

The authors develop size-consistent interpolation models along the MP adiabatic connection that accurately describe non-covalent interactions without dispersion corrections.

Findings

Reduce MP2 errors in c6-stacking complexes

Competitive with state-of-the-art dispersion functionals

Outperform existing methods on datasets like CT7 and L7

Abstract

Given the omnipresence of non-covalent interactions (NCIs), their accurate simulations are of crucial importance across various scientific disciplines. Here we construct accurate models for the description of NCIs by an interpolation along the M{\o}ller-Plesset adiabatic connection (MP AC). Our interpolation approximates the correlation energy, by recovering MP2 at small coupling strengths and the correct large-coupling strength expansion of the MP AC, recently shown to be a functional of the Hartree-Fock density. Our models are size consistent for fragments with non-degenerate ground states, have the same cost as double hybrids and require no dispersion corrections to capture NCIs accurately. These interpolations greatly reduce large MP2 errors for typical $\pi$-stacking complexes (e.g., benzene-pyridine dimers) and for the L7 dataset. They are also competitive with state-of-the-art dispersion enhanced functionals and can even significantly outperform them for a variety of datasets, such as CT7 and L7.