We have also assessed the performance of HF+D(EFP) on the S66×8 data set of dimers, where the monomers are all charge-neutral, in order to test whether the results above are somehow an artifact of the ionic liquid data set. (Dimers containing acetylene were excluded from these calculations because the Q-Chem/libEFP interface does not handle linear fragments at the present time.) Error statistics are shown in Fig. and suggest that the general behavior is quite similar to what we observed for ionic liquid constituent dimers.