We next examine agreement between MM-optimized geometries and those from QM, as calculated by each molecule's root-mean-square deviation of atomic positions (RMSD) and Torsion Fingerprint Deviation (TFD) scores with reference to the parent QM-optimized geometry. While RMSD is the more common metric, it depends on the molecule size, complicating interpretation. In contrast, TFD was designed to be more independent of molecule size in order to compare molecular conformations more meaningfully. The TFD score between two molecular structures is evaluated by computing, normalizing, and Gaussian weighting the (pseudo-)torsion deviation for each bond and ring system. While TFD is normalized from 0 to 1, RMSD is unbounded. Both RMSD and TFD are similar in that a higher value signifies lower agreement between the geometries of two molecules. A FF which yields optimized geometries closer to those of QM would have generally smaller RMSD and TFD values. We calculated RMSD and TFD scores for all MM optimized geometries with respect to QM geometries. We plotted this data in histograms, in Figure .