Here, ∆E HF int is the counterpoise-corrected HF interaction energy. The two second-order quantities in eq. 4 are response ("resp") analogues of the second-order terms in eq. 2, and these require the solution of coupled-perturbed HF equations. For SAPT0(KS) calculations, the firstand second-order SAPT terms in eq. 4 should be computed at the HF level even if the corresponding terms in eq. 1 are computed based on KS orbitals. Notably, δE HF is the only term in eq. 1 that requires self-consistent field (SCF) iterations in a dimer basis set, which becomes a bottleneck for large monomers.