Reactive Molecular Dynamics of Detonating Petn

We investigate the initial chemical events sustaining a detonation in shock-compressed PETN resulting from intermolecular collisions behind the shock wave using first-principles reactive molecular dynamics. The reaction dynamics of bimolecular collisions was studied as a function of collision velocities and crystallographic orientations. For each orientation, threshold collision velocities of reaction, and products of decomposition were determined. The timescale of reaction was evaluated and used to understand whether these initial chemical events are largely driven by reaction dynamics, or temperature. Bond dissociation energies were calculated and used to rationalize the outcome of the chemical events in the course of the reaction dynamics. Finally, the relationship between orientation dependent sensitivities and steric factors is discussed.