is the so-called "δHF" correction . It uses a counterpoise-corrected, supramolecular HF interaction energy (∆E HF int ) to correct the SAPT0 interaction energy for induction effects beyond second order in perturbation theory, which is crucial for the accurate description of hydrogen bonds . See Ref. 63 for a definition of the second-order response ("resp") energies that appear in Eq. ( ).