A series of density functional theory (DFT)-based methods, including ranked and non-ranked submissions, were also used here. In SAMPL6, a DFT-based approach yielded good quantitative results , though without geometry optimizations employed in the current challenge. Here, the QM DFT-based B2PLYPD3/SMD submissions use B3PW91 with GD3BJ to treat dispersion, B2PLYPD3 for single point energy calculations , and the SMD implicit solvation model . Different submissions in this series differed in which basis set was chosen for geometry optimization . Overall, these methods were roughly in the middle of all submitted methods in terms of predictive accuracy. All of these QM methods yield binding free energies for most guests which are too negative, with ME values of 2.69 kcal/mol or greater, and this is especially true for cationic guests binding exo-OA. The participants also highlighted particular difficulties with chlorine-containing guest g2. In initial tests, the OA-g2 binding free energy was estimated to be close to -30 kcal/mol, while experimental value in literature was -6.91 kcal/mol . In the combined GDCC dataset, the ranked B2PLYPD3/SMD_QZ-R method was within 2 kcal/mol of experiments in three of nine cases and correctly predicted exoOA-g1 to be a non-binder. Overall, it appears that QM methods are not yet competitive with the best other approaches for these systems, and potentially, that molecules containing halogens can be particularly problematic.