Development of Reactive Force Field for DNTF and Molecular Dynamics Simulation of Reaction Mechanism under Shock Loading

3,4-Dinitrofurazanfuroxan (DNTF) is a typical hydrogen-free furazan compound with good casting performance. A rapid chemical reaction under shock loading causes the high impact sensitivity of DNTF. However, the details of the reaction remain unclear. Currently, there is no suitable reactive force field (ReaxFF) for simulating the reaction under shock loading because the existing ReaxFF parameters cannot accurately reproduce the structure of furazan during relaxation at room temperature. Therefore, the ReaxFF parameters are reoptimized using a program designed by ourselves based on the training set that takes into account the structure and decomposition products of DNTF. The obtained ReaxFF accurately describes the structure of the DNTF molecule. A method is proposed to number molecules, groups, and atoms and track the reaction path of each atom to obtain the cleavage and formation of bond. The furoxan N-O bond breaks first, which is the trigger bond. Subsequently, the C-NO₂ group dissociates, and the N-O bonds in the furazan break. Cleavage of the furoxan trigger bond, furazan opening, and C-NO₂ dissociation are the main initial decomposition mechanisms of the reaction, and the order of reaction activation energy was C-NO₂ ≈ furazan ring > furoxan ring. The rapid formation of N-N and C-O bonds after the ring opening and C-NO₂ dissociation is the main reason for the rapid increase in temperature.