A Photophysical Deactivation Channel of Laser-Excited TATB Based on Semiclassical Dynamics Simulation and TD-DFT Calculation

Wenying Zhang, Jian Sang, Jie Cheng, Siyu Ge, Shuai Yuan, Glenn Lo, Yusheng Dou
2018 Molecules  
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
more » ... led to a significant increase of the C-NO 2 bond length, which suggests that C-NO 2 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 S 1 excited states for each configuration in the simulated trajectory. The S 1 ←S 0 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.
doi:10.3390/molecules23071593 pmid:29966325 fatcat:kzcvejx35bgc7iwc75jhhxgyea