Abstract
A deactivation channel for laser-excited 1,3,5-triamino-2,4,6-trinitrobenzene (TATB) was studied by semiclassical dynamics. Results indicate that the excited state resulting from an electronic transition from the highest occupied molecular orbital (HOMO) to the lowest unoccupied molecular mrbital (LUMO) is deactivated via pyramidalization of the activated N atom in a nitro group, with a lifetime of 2.4 ps. An approximately 0.5-electron transfer from the aromatic ring to the activated nitro group led to a significant increase of the C–NO2 bond length, which suggests that C–NO2 bond breaking could be a trigger for an explosive reaction. The time-dependent density functional theory (TD-DFT) method was used to calculate the energies of the ground and S1 excited states for each configuration in the simulated trajectory. The S1←S0 energy gap at the instance of non-adiabatic decay was found to be 0.096 eV, suggesting that the decay geometry is close to the conical intersection.
Highlights
Energetic materials refer to organic substances that can store a large amount of chemical energy
Femtosecond laser pulses were applied to the equilibrium structure with a full-width at half maxima (FWHM) of 50 fs and photon energy of 3.2 eV (387 nm), which corresponds to the lowest unoccupied molecular mrbital (LUMO)–highest occupied molecular orbital (HOMO) energy gap
The charge transfer leads to the obvious increase of the C–NO2 bond and formation of the C–N σ bond
Summary
Energetic materials refer to organic substances that can store a large amount of chemical energy. Under the action of external stimuli, such as shockwave and light, energetic materials readily decompose and release energy [1,2,3]. Irradiation by an ultraviolet or visible laser can be used to electronically excite a molecule, which can undergo a series of photochemical and photophysical processes, including radiative transitions and nonradiative deactivation. Nonradiative deactivation can involve internal conversion and intersystem crossing; internal conversion is considered to be a crucial first step for an explosive decomposition reaction because the vibrational energy generated by the deactivation can lead to the breaking of chemical bonds, triggering a chain reaction that eventually releases the stored chemical energy. Nitro-explosives are among of the most important energetic materials
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
