COMP 251

Unlike other nitramines like RDX/HMX we found only one distinct initial reaction channel (homolysis of N–NO2 bond) during unimolecular decomposition. We did not observe any HONO elimination reaction under these circumstances. Whereas, ring breaking reaction followed by NO2 fission. Therefore, in spite limited sampling that provide mostly qualitative picture, we proposed scheme of unimolecular decomposition of CL-20 .The averaged products population over all trajectories is estimated at 4 HCN, 2-4 NO2, 2-4 NO, ~1 CO, and ~1 OH molecule per one CL-20.

Our simulations provide a detailed description of the chemical processes in the initial stages of thermal decomposition condensed CL-20. They allow us to elucidate key features of such process: composition of primary reaction products, reaction timing, Arrhenius behavior of the system, etc. They clearly indicate that the primary reactions leading to NO2, NO, N2O and N2 occur at very early stages. We also estimate activation barrier for the formation of NO2 which is essentially determines overall decomposition kinetics and effective rate constants for NO2 and N2. Calculated bulk decomposition pathways correlates with available condensed phase experimental data. Unfortunately, comparison of the predicted gas phase mechanism is not possible.