The propene end-products predicted by our BOMD simulations corroborates previous experiments on DIMP, which include thermal decomposition studies, pyrolysis and combustion in nitrogen/oxygen-rich environments, 57 as well as microwave and laser-induced decomposition under inert environments. Collectively, all of these prior experimental studies detected propene as one of the main by-products of DIMP decomposition, which further supports our BOMD predictions. To further investigate the decomposition of DIMP on alumina, we utilized well-tempered metadynamics simulations by adopting two collective variables. We performed two sets of metadynamics simulations (for each temperature within the 200 -1000 • C range) using different initial conditions. Obtaining accurate free energy profiles from metadynamics simulations requires (1) longer simulation times until all acces- sible regions of the potential are explored (with trajectories spanning forward and backward many times between reactant and product states) and ( ) a careful selection of collective variables. Our well-tempered metadynamics simulations at various temperatures suggests that when the C-O bond is broken, subsequent reforming of this bond is prohibited (Figure ), which indicates that the reaction is irreversible. The Supporting Information (Figures and) provides further details on the convergence of our free energy profiles between the transition state and reactant basin as a function of time, which demonstrates that our metadynamics simulations are fully converged. In the Supplementary Material, we provide an additional free energy profile (Figure ) at 1000 • C that utilizes different initial conditions. For this separate case, the reactant proceeds to the product state via a stable transition state with a tiny minimum, and the activation barrier is ∼6.36 kJ/mol. Collectively, the average free energy value from these independent trajectories is 5.24 kJ/mol.