McGrane S D, Bolme C A, Greenfield M T, Chavez D E, Hanson S K, Scharff R J
Shock and Detonation Physics Group, , ‡High Explosive Science and Technology Group, and §Nuclear and Radiochemistry Group, Los Alamos National Laboratory , Los Alamos, New Mexico 87545, United States.
J Phys Chem A. 2016 Feb 18;120(6):895-902. doi: 10.1021/acs.jpca.5b11851. Epub 2016 Feb 3.
High explosives that are photoactive, i.e., can be initiated with light, offer significant advantages in reduced potential for accidental electrical initiation. We examined a series of structurally related tetrazine based photoactive high explosive materials to detail their photochemical and photophysical properties. Using photobleaching infrared absorption, we determined quantum yields of photochemistry for nanosecond pulsed excitation at 355 and 532 nm. Changes in mass spectrometry during laser irradiation in vacuum measured the evolution of gaseous products. Fluorescence spectra, quantum yields, and lifetimes were measured to observe radiative channels of energy decay that compete with photochemistry. For the 6 materials studied, quantum yields of photochemistry ranged from <10(-5) to 0.03 and quantum yield of fluorescence ranged from <10(-3) to 0.33. In all cases, the photoexcitation nonradiatively relaxed primarily to heat, appropriate for supporting photothermal initiation processes. The photochemistry observed was dominated by ring scission of the tetrazine, but there was evidence of more extensive multistep reactions as well.
