Infrared study of 1,3,5-triamino-2,4,6-trinitrobenzene under high pressure

Abstract

We report synchrotron Fourier transform infrared measurements of 1,3,5-triamino-2,4,6-trinitrobenzene in the mid-IR and far-IR spectral regions up to $\sim 10\mathrm{GPa}$, using KBr or petroleum jelly to compress the samples. During the far-IR experiment, we cycled the pressure, measuring IR spectra at various pressures, to determine whether the sample survived. In both experiments, no phase transition was observed. In the high frequency region $(\sim 3000{\mathrm{cm}}^{-1})$, the peak frequencies of the $\mathrm{N}{\mathrm{H}}_2$ symmetric and antisymmetric vibrational modes decrease with increasing pressure, indicating strengthening of intermolecular hydrogen bonding with pressure.