Pressure-Induced Conformer Modifications and Electronic Structural Changes in 1,3,5-Triamino-2,4,6-trinitrobenzene (TATB) up to 20 GPa

Abstract

To probe the behavior of structural evolution and optical properties in solid energetic material TATB, X-ray diffraction (XRD) and Raman and absorption spectroscopy were performed under high pressure up to 20 GPa. The absorption edge shifts to red, and the color significantly varies with increasing pressure for TATB. The XRD patterns under high pressure indicate that TATB maintains the triclinic structure within this pressure range. An electronic structural change is observed at ∼5 GPa, resulting from the modification of conformers of TATB, which is associated with the rotation of nitro and amino groups under high pressure. The current experimental results clarified the absence of phase transition below 20 GPa and confirmed that the pressure-induced color change originates from the enhancing conjugation of π orbital due to the shorting C–NO2 bonds and the rotation of nitro groups with increasing pressure. The third-order Birch–Murnaghan equation of state is obtained up to 16.5 GPa, which is helpful for calculating researchers to verify the correctness of their models.

Distance makes a difference in crystalline photoluminescence

“…21 . The peak position “redshifts” upon compression correspond to the pressure-induced decrease of lattice constants and indicate the decrease of interparticle distance 45 , which was verified by the fact that the peak positions were restored under decompression, see Supplementary Fig. 21 .…”

Pressure-induced phosphorescence enhancement and piezochromism of a carbazole-based cyclic trinuclear Cu(i) complex

“…19,20 To date, the molecular design and material selection for piezochromism are mostly focused on organic molecules. [21][22][23][24][25] Owing to weak spin-orbital coupling and a long triplet-state lifetime, the pure organic molecules hardly showed strong phosphorescence at room temperature (rt). 26,27 Thus, most of piezochromic luminescent materials display a pressure-induced fluorescence change at rt (e.g., quenched or enhanced intensity and batho-/hypsochromic shift), 5,12,20 while pressure-induced phosphorescence enhancement (PIPE) materials still remain unexplored and highly challenging.…”

Phase Transition Routes for ε- and γ-CL-20 Crystals under High Pressures of up to 60 GPa

“…Single-component explosives are compounds which contain explosive groups. The most important explosive groups are −C–NO 2 , −O–NO 2 , and −N–NO 2 , corresponding to several major types: nitrides represented by TNT, TATB, LLM-105, and so on, nitrates represented by PETN, NG, and so on, and nitramines represented by RDX, HMX, CL-20, and so on. − …”