So far, we showed that the model can well reproduce energy barriers close to DFT accuracy on structures from MD trajectories and synthetic ones. However, as mentioned previously in subsection 2.1, realistic energy barriers are expected to be closer to those computed for at least partially optimized systems. But, since optimizations at the DFT level of theory for the entire data set are prohibitively expensive, only a subset of reaction paths were optimized on the BMK/6-31+G(2df,p) level of theory. The mean absolute deviation between the barriers computed based on geometries from MD, and based on DFT optimized geometries is 13.6 ± 11.6 kcal/mol (Figure ). This deviation highlights the importance of the geometry optimization and the transferlearning step detailed in the following section. Importantly, as expected, optimized barriers are lower than the BDE of the dissociating bond of the reaction, in contrast to the unoptimized data set with unfavorable paths in case of large reaction distances (see