Simulation of Thermal Decomposition of RDX by Reactive Molecular Dynamics

By stimulating Cylotrimethylenetrinitramine (RDX) through exerting temperature or mechanical impact or friction, decomposition reaction occurs at very high rate. Molecular dynamic technique and LAMMPS code with ReaxFF-lg were employed to simulate initiation of RDX. Potential energy variations of the system were calculated over time for five different temperatures up to 3 nanoseconds and the products of decomposed system respect to time were determined at each stage of stimulation for different values of temperature and thermal initiation stimulation energy in NVE and NVT ensembles. The activation energy of decomposition was calculated 24.13 Kcal.mol-1 through Arrhenius equation. The minimum needed temperature to produce hydrogen molecules with temperature decomposition was about 2500 K and production times for several conditions were calculated. The amount of nitrogen and hydrogen production were increased with raising temperature and reached maximum at 3000 K. Maximum values of nitrogen and hydrogen production were at 3000 K. The time required to complete the decomposition reaction was 2000 picosecond at 2500 K.