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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 -stacking complexes (eg, 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.
Publication date: 
10 Apr 2021

Timothy J Daas, Eduardo Fabiano, Fabio Della Sala, Paola Gori-Giorgi, Stefan Vuckovic

Biblio References: 
arXiv preprint arXiv:2104.04793