  The effects of circular voids on the shock sensitivity of a two-dimensional
model high explosive crystal are considered. We simulate a piston impact using
molecular dynamics simulations with a Reactive Empirical Bond Order (REBO)
model potential for a sub-micron, sub-ns exothermic reaction in a diatomic
molecular solid. The probability of initiating chemical reactions is found to
rise more suddenly with increasing piston velocity for larger voids that
collapse more deterministically. A void with radius as small as 10 nm reduces
the minimum initiating velocity by a factor of 4.

Materials Science