Noncovalent interactions from models for the Møller-Plesset adiabatic connection

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 Møller-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 πstacking 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.