The Low-Temperature Vibrational Behavior of Pentaerythritol Tetranitrate

: The authors report the room temperature Raman and synchrotron Fourier transform infrared measurements of pentaerythritol tetranitrate (PETN), as well as low-temperature Raman measurements from 4 to 298 K up to ~15 GPa, using a helium gas pressure medium. No evidence of phase transitions was observed in the pressure/temperature range studied, although the molecular symmetry of PETN is modified from S4 to D2 near 8.1 GPa. The modification was not found to be temperature dependent, and decompression studies indicated the reversibility of the symmetry change.