Only the highest-quality basis sets that we can afford for this system, def2-TZVPD and jun-cc-pVTZ, afford interaction energies that begin to approach the CCSD(T)/ CBS benchmark, although even these XSAPT + MBD values are overbound by ≈ 1.7 kcal/mol in the absence of the δE HF correction. When that correction is included (δE HF = -2.9 kcal/mol), the XSAPT + MBD interaction energy moves even further away from the CCSD(T)/CBS value, and further still from the QMC . For the Karlsruhe basis sets, the difference between minimal and full augmentation is mostly insignificant (equal to 1.0 kcal/mol at the doubleζ level but much smaller in larger basis sets), whereas the difference between jun-cc-pVXZ and aug-cc-pVXZ (X = D or T) is completely insignificant. It is worth noting that jun-cc-pVXZ retains some higher-angular momentum diffuse functions beyond minimal augmentation and these appear to be adequate to afford an interaction energy that is converged with respect to inclusion of further diffuse functions. we have applied to this system, yet remains somewhat overbound with respect to the DLPNO-CCSD(T)/CBS benchmark (|E int | = 21 kcal/mol 103 ). As in the DNAellipticine case, the QMC benchmark is somewhat less strongly bound (|E int | = 18 kcal/mol 104 ).