We use the MLIP generated by WTMetaD-IB to calculate the free energy of R2 along the reaction coordinate of r 1 -r 2 using US and WTMetaD. The US/MLIP-MD calculations used MD. These values are in good agreement with the reported experimental value in pentene (29.2 ± 1.1 kcal mol -1 at 365.6 K, Fig. ). Moreover, the TS geometries obtained from both methods deviate by only 0.01 Å from the DFT-optimised TS geometry (r 1 -r 2 = -0.10 Å) along the reaction coordinate. These results further confirm the accuracy of the MLIP, besides the prediction of energies and forces.