Sets for XSAPT + MBD Using S66. We next consider the performance of the hybrid XSAPT + MBD method as applied to the S66 dimers. These systems are small, with the largest being pentane dimer, and thereby facilitate high-throughput testing. XSAPT + MBD errors for each of the S66 dimers are plotted in Fig. across a wide range of Pople, Karls- Fig. : Dispersion energies for the S66 dimers computed at the SAPT0/jun-cc-pVXZ level. Shaded regions delineate the three subsets of S66: hydrogen-bonded dimers (1-23), dispersion-dominated complexes (24-46), and dimers with mixed-influence interactions (47-66).