Prediction of reaction kinetics for CL-20 and host-guest crystals under high temperature and pressure using neuroevolution potential

The energetic host-guest approach has been successfully applied to design various novel crystal structures. A neuroevolution potential was proposed to predict the reactive kinetics of CL-20 crystals under high temperature and pressure. In this study, molecular dynamics simulations were conducted to investigate the shock compression and thermal decomposition behaviors. During the shock compression process, temperature monitoring revealed the transition of the crystal from the unreacted Hugoniot state to the reacted Hugoniot state, which occurred after the decomposition of CL-20 molecules. The temperature rise in the reacted state followed the order: N₂O > CO₂ > H₂O₂ > NCCH₃ > β > α > γ > ϵ. These indicate that guest molecules facilitate the reaction under shock conditions. During the thermal decomposition process, monitoring the potential energy evolution showed that the initial decomposition of CL-20 molecules is an endothermic reaction, primarily producing NO₂. As the temperature increased, NO₂ was further consumed, and CL-20 underwent a ring-opening reaction, primarily generating CO₂. NCCH₃ and H₂O₂ molecules were consumed during the endothermic process, showing the largest and smallest potential energy changes, respectively. N₂O molecules were consumed during the formation of final products, while CO₂ and H₂O were the final products and were not consumed. The activation energy ranking of the reactions was ϵ > β > γ > NCCH₃ > N₂O > CO₂ > α > H₂O₂. These results provide an atomic-level perspective for controlling the detonation performance of energetic materials under high temperature and pressure.