The VENUS program was used to perform QCT calculations on the PIP-NN PES to simulate the unimolecular isomerization dynamics. In these simulations, CH3NC was excited with classical microcanonical sampling with specific total vibrational energies of 4.336, 5.204 and 6.505 eV, denoted as 𝐸vib, while rotational energies were excluded. Such high vibrational energies are needed for the observation of sufficient amounts of isomerization within the time scale. The QCT simulations are time propagated without constraints, and terminate once CH3NC → CH3CN isomerization occurs, which is identified by inspecting the change of the CNC angle, as used in ref. . At a CNC angle of 90°, the molecule is considered to reach the transition state and would not revert, which means recrossing of the trajectories back to the reactant is not considered in this work. For each 𝐸vib, 100,000 simulations are conducted, and plots of ln[N(t)/N(0)] vs. time are given for discussion, where N(t)/N(0) in this work represents the relative number of CH3NC remaining vs. time.