Compression behavior and spectroscopic properties of insensitive explosive 1,3,5-triamino-2,4,6-trinitrobenzene from dispersion-corrected density functional theory

Using dispersion corrected density functional theory,we systematically examined the pressure effect on crystal structure,cell volume,and band gap of 1,3,5-triamino-2,4,6-trinitrobenzene(TATB)to understand its extraordinary chemical stability.Analysis of the Mulliken population and the electron density of states implied a possible charge transfer in TATB with increasing pressure.Raman and infrared spectra of TATB under hydrostatic pressure up to 30 GPa were simulated.The observed strong coupling between NH_2 groups and NO_(2) groups with increasing pressure,which is considered to have a tendency of energy transfer with these vibrational modes,was analyzed.The pressure-induced frequency shift of selected vibrational modes indicated minor changes of molecular conformation mainly by the rotation of NH_(2) groups.Compression behavior and spectroscopic property studies are expected to shed light on the physical and chemical properties of TATB on an atomistic scale.