Photoinitiation of energetic materials: New ways to achieve tunable sensitivity

Sensitivity to initiation of detonation of energetic materials (EM) is a complex process detailed mechanisms of which have yet to be established. Laser irradiation opens up new opportunities in triggering and controlling explosive decomposition of EM. It has been long realized that electronically excited states play a key role in explosive chemistry, but only recent studies demonstrated an actual laser-stimulated photochemical initiation of EM. Precise tuning of sensitivity to initiation via photo-excitation appears challenging because all secondary explosives are insulators with band gaps of 4-8 eV. We will discuss feasible mechanisms of photocatalytic decomposition of explosives triggered by the laser excitation with low energies (1.17-2.5 eV). The key in tuning the sensitivity of EM to initiation of chemistry is in the controlled modification of the electronic structure of the explosive-metal oxide interfaces. We will explain how the morphology of metal oxide additives or photoactive organic molecules, their interactions with EM crystalline matrix and laser excitation serve to generate a high density of excited and charged states in the EM composites. -/abstract- Authors: M.M. Kuklja, R. Tsyshevsky, S.N. Rashkeev, F. Wang, A.S. Zverev, A.Y.