Quantum mechanical simulations of condensed-phase decomposition dynamics in molten RDX

Abstract

A reaction rate model of condensed-phase decomposition hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) under pressures up to several GPa is needed to support mesoscale simulations of the energetic material's response to thermal and shock loading. A prerequisite to developing such a model is the identification of the chemical pathways that control the rate of initial dissociation and subsequent decomposition of molecular fragments. Presented here are density functional theory based molecular dynamics simulations of reactive dynamics in molten RDX at an initial temperature of 1500 K and different values of the melt density chosen to probe the effect of hydrostatic compression. The observed dissociation mechanisms and the effect of pressure on the corresponding rate constants are discussed.