Figure (a) shows a clear correlation between the storage energies computed with GFN2-xTB and corresponding DFT energies. This means, that molecules that have large storage densities with GFN2-xTB can be expected to have large DFT storage densities. The correlation between DFT and PM3 back reaction barriers in Figure ) is less clear, since the groups are overlapping. However, molecules that have high barriers with DFT also have high barriers with PM3, which is sufficient for screening purposes. The the vertical and horizontal lines indicate the DFT and PM3 barrier heights for the parent system (119 and 165 kJ/mol) and show that PM3 tends to overestimate the number of molecules with barriers higher than that of the parent compound. Thus, using the a PM3 barrier cutoff of 165 kcal/mol should retain all molecules with a DFT barrier height that is higher than that of the parent compound, including many false positives. Alternatively, the cutoff can be raised up to 180 kJ/mol (dotted horizontal line) to reduce the number false positives without loosing too many true positives.