Reaction Network of Ammonium Perchlorate (AP) Decomposition: The Missing Piece from Atomic Simulations

The decomposition network of ammonium perchlorate (AP) is essential for combustion performance and safety of solid propellants, while the detailed reaction pathway during thermolysis is far from clear due to the ultrafast and complex reactions involved. Herein, we present direct atomic simulations of AP thermal decomposition and propose a detailed decomposition network to fill the missing piece in the kinetic models by using a neural network model derived from ab initio calculations. The proton transfer is the dominant channel (NH4 + ClO4 → NH3 + HClO4), which is also observed in previous mass spectra experiments. In addition, gas products from decomposition play a critical role in promoting the decomposition of solid AP. For example, the H abstraction reaction by OH is found to be a critical pathway for AP decomposition. These simulations provide atomic insights into the complex reaction dynamics of AP and can be extended to investigate the reaction mechanism of novel energetic materials.