Simulated thermal decomposition and detonation of nitrogen cubane by molecular dynamics

Abstract

We present simulations of a model molecular solid of nitrogen cubane subject to thermal agitation and mechanical shock. A new approach, a reactive state summation potential, has been used to model nitrogen cubane dissociation. At elevated temperatures, the system decomposes to N(2) mixed with a small amount of oligomeric nitrogen. When subject to shock loading the system detonates above some critical threshold after which a shock front is self-sustained by the energy release from chemical reactions at a constant intrinsic speed. This is the first example of a fully three-dimensional atomic simulation of a chemically-sustained detonation. The spatial confinement of the shock front results in longer chain intermediates than in the case of thermal decomposition, suggesting that shock intermediates can be structurally very different from the same material subject to comparable temperatures and pressures.