We are interested in low-barrier reactions, which we in this study define as barriers below 50 kcal/mol (Figure ). To screen the remaining reactions on their barriers, we use barrier estimates based on the RMSD-PP approach using GFN2-xTB as described in . As barrier estimates were seen to vary between runs, we calculate a barrier estimate for each reaction five times and keep the lowest one. In case all of the barrier estimate computations fail, we discard the reaction. We then discard all reactions with barriers above 50 kcal/mol. Finally, the remaining reactions are checked with DFT (B3LYP/6-31+G(d) ) as in the original studies . The reaction energies are computed as described above and the barriers and transition states (TSs) are computed and verified by IRCs . The TS is found for all of the cases where the barrier estimate is below 50 kcal/mol. A linear interpolation (10 points from maximum energy structure to both neighbours in the RMSD-PP path) is performed and the interpolated structures are subjected to single point energy calculations using DFT. The maximum energy structure based on DFT calculations is used as initial guess for the TS structure in a DFT TS search using Gaussian [opt=(calcall, ts, noeigen)]. The procedure is the same for GFNx-xTB verification of the TSs using a custom script to interface xtb with Gaussian.