Trigger linkage mechanism: Two or multiple steps initiate the spontaneous decay of energetic materials

Abstract

The trigger linkage mechanism is usually employed to describe the spontaneous decay of energetic materials (EMs) when they are sufficiently stimulated. Based on this mechanism, large numbers of correlations between sensitivity and the strength of the weakest bond have been established. As an important aspect of the trigger linkage mechanism, it is necessary to clarify whether the trigger linkage mechanism proceeds along the one-step-reaction mechanism (OSRM) or the two-or-multiple-step-reaction mechanism (TMSRM). Based on a series of molecular dynamics simulations of the thermal decay of gaseous and solid EMs, this study confirms that the cleavage of the weakest bond alone is insufficient to initiate the spontaneous decay of EMs even though it usually takes place as the first step. The spontaneous decomposition occurs always later than the first cleavage of the trigger linkage and requires additional energy besides the bond dissociation energy, indicating that the trigger linkage mechanism proceeds along the TMSRM rather than the OSRM. This partly accounts for the roughness of many OSRM-based theories and methods for assessing the chemical stability of EMs, which are expected to be much improved since not only the first cleavage of the weakest bond but also a further step should be sufficiently considered as a true rate-determining step with increasingly strengthened computation capacity.

Topics & Concepts