Exploring the Thermal Decomposition Mechanism of Nitromethane Via a Neural Network Potential

Abstract

A new neural network potential (NNP) is constructed to reveal the thermal decomposition mechanism of nitromethane (NM). The NNP model possesses both ab initio accuracy and empirical force fields efficiency, which allows the investigation of the entire decomposition process of NM from an atomic perspective. A series of molecular dynamics simulations are performed for NM decomposition, and the main reaction channels are further examined with transition state theory and quantum calculation. The results show that the C-N bond breaking is the dominant initial decomposition channel of NM at high temperature, and the stable product H2O can be consumed for the formation of NH3 and CO2. The complex reaction network is established, and the generation process of each main product is discussed in detail. The NNP gives an atomic insight into the complex reaction dynamics of NM and can be extended to investigate the reaction mechanism of more CHON based energetic materials.

Keywords: Molecular dynamics, Decomposition mechanism, Neural network potential, Nitromethane