Coupled Thermal and Electromagnetic Induced Decomposition in the Molecular Explosive αHMX; A Reactive Molecular Dynamics Study

We use molecular dynamics simulations
with the reactive potential ReaxFF to investigate the initial reactions
and subsequent decomposition in the high-energy-density material α-HMX
excited thermally and via electric fields at various frequencies.
We focus on the role of insult type and strength on the energy increase
for initial decomposition and onset of exothermic chemistry. We find
both of these energies increase with the increasing rate of energy
input and plateau as the processes become athermal for high loading
rates. We also find that the energy increase required for exothermic
reactions and, to a lesser extent, that for initial chemical reactions
depend on the insult type. Decomposition can be induced with relatively
weak insults if the appropriate modes are targeted but increasing
anharmonicities during heating lead to fast energy transfer and equilibration
between modes that limit the effect of loading type.