The term ∆E KS that is defined in Eq. ( ) represents the difference brought about in the HF interaction energy by including electron correlation in the zeroth-order wavefunctions used for subsequent intermolecular energy corrections. This implies that the quantity ∆E dlKS int defined in Eq. ( ) can be interpreted as a "dispersionless" KS interaction energy, which is added to SAPT(KS) dispersion and XPol polarization in Eq. (43).