Effects of oxidant molecules on the thermal decomposition of 4,7-diaminopyridazino[4,5-c]furanoxane crystal: Ab initio molecular dynamics simulations

Inserting oxidant molecules into the crystal voids to form oxidant cocrystal can greatly enhance the detonation properties of energetic materials. Therefore, oxidant cocrystals are regarded as one type of potential candidates of high energy density materials. The effects of the oxidants (HNO3 and HClO4) on the thermal decomposition mechanisms of two oxidant cocrystals (DPF(4,7-diaminopyridazino[4,5-c] furanoxane):HNO3 and DPF:HClO4) were investigated by ab initio molecular dynamics (AIMD). AIMD simulations are performed using a NVT ensemble. The temperature was controlled by a Nos & eacute; thermostat. First, we performed 5 ps simulations at 298.15 K to get an equilibrium system. Then, the simulations were performed at 3000 K with a time step of 1 fs and a total time of 15 ps. The initial degradation pathways of the two cocrystals have the same and involve the cleavage of the N-H and N-O bonds. Five different decay pathways were found in the subsequent reactions: intermolecular H transfer, N-O bond cleavage, N-N bond cleavage, and C-C bond formation and cleavage. Both HNO3 and HClO4 can promote the formation of N-2, H2O and CO2, but only have a certain effect. Different oxidant molecules hardly affect the initial and subsequent decomposition paths of DPFH.