Laser Initiation of Energetic Materials: Selective Photoinitiation Regime in Pentaerythritol Tetranitrate

We describe and analyze the selective (resonance) laser-induced initiation of chemical decomposition reactions in pentaerythritol tetranitrate (PETN, C 5 H 8 N 4 O 12 ) and propose a potential mechanism for the phenomenon. On the basis of our experiments, the photoinitiation of PETN is a two-stage process that is comprised of a laser-induced optical excitation of the molecule with an activation energy of 1.17 eV (1060 nm) by a neodymium phosphate glass laser followed by the thermal decomposition of the excited state with an energy barrier of 0.4 eV. We also illustrate that the small efficiency of the optical absorption of PETN at this wavelength can be enhanced by the MgO light-scattering additives, which significantly increase the absorption due to multiple scattering incidents in PETN. The resonance photoinitiation clearly demonstrates a possibility for designing tunable explosive material systems and identifies ways to control the sensitivity of the materials to rapid decomposition.