Photoactive High Explosives: Substituents Effects on Tetrazine Photochemistry and Photophysics

Abstract

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.

Extreme Stabilization and Redox Switching of Organic Anions and Radical Anions by Large-Cavity, CH Hydrogen-Bonding Cyanostar Macrocycles

“…Therefore, the tetrazine's cathodic reduction peak served as an internal standard set to −1.00 V on account of the fact that tetrazine reduction potentials are largely insensitive to substitution. 33,36,63,73 We see clear evidence of switching from the CVs (Figure 6). The solution of MPTz alone (Figure 6a) shows a reversible one-electron reduction process typical of tetrazines (E 1/2 = −0.94 V).…”

“…Consequently, there were minor variations (±50 mV) in potential values between experiments. Therefore, the tetrazine’s cathodic reduction peak served as an internal standard set to −1.00 V on account of the fact that tetrazine reduction potentials are largely insensitive to substitution. ,,, …”

Coulomb Explosion Dynamics of Multiply Charged para-Nitrotoluene Cations

“…Electronic excitation, ionization, and electron-ion coupling play crucial roles in shock initiation of energetic materials. − In particular, ionization of the parent energetic molecules lowers the barrier to molecular dissociation in explosives including TNT, RDX, and PETN, thereby facilitating the initiation of detonation. , Moreover, laser initiation of photoactive explosives produces electronic excited states and ions to selectively initiate detonation. − Hence, knowledge of the initial dissociation pathways of ionized energetic molecules is important for advancing the understanding of initiation mechanisms in energetic materials and designing safer photoactive explosives.…”

Iron and Copper Doped Zinc Oxide Nanopowders as a Sensitizer of Industrial Energetic Materials to Visible Laser Radiation

“…Photocatalytic chemical reactions are widely applied to solve various technical tasks in various fields such as modern green energy, water purification, organic synthesis, and medicine [ 15 , 16 , 17 , 18 , 19 ]. The role of photochemical processes in the laser initiation of an EM has been discussed since the first publications on this topic [ 20 ] and is still relevant today [ 21 , 22 , 23 , 24 , 25 ]. The key property of radiation is its ability to transfer the energetic material molecule to an excited state from which the decomposition process can occur with no or a lower potential barrier.…”