An Infrared Study of Secondary Explosives under High Pressure.

We report synchrotron FTIR and far infrared measurements on PETN, RDX, HMX and TATB at ambient temperature and high pressure, using various media for pressurization of the samples. In all cases, we have carefully studied any phase transitions in the 0 - 15GPa pressure range and have cycled pressures to interrogate sample survivability and reproducibility of the phase sequences. For PETN, we used differing pressurizing media (Ar and KBr) and have found that the onset of a prior-reported phase transition around 5GPa varies with the different media, portending the importance of sheer stress in inducing some or all of this phase transitions.