Understanding discrepancies in noncovalent interaction energies from wavefunction theories for large molecules

This is the authors' abstract. We don't add key points for this paper.

Are the currently used reference methods to approximately solve the many-electron Schrödinger equation accurate enough? Here, we investigate recently reported discrepancies of noncovalent interaction energies for large molecules predicted by two of the most widely-trusted many-electron theories: diffusion quantum Monte Carlo and coupled-cluster theory. We are able to unequivocally pin down the main source of the puzzling discrepancies and present modifications to widely-used coupled-cluster methods needed for more accurate noncovalent interaction energies of large molecules on the hundred-atom scale. This is of critical impact for a wide range of applications which rely on highly-accurate interaction energies between large and polarizable molecules.