title: High pressure-high temperature decomposition of γ-cyclotrimethylene trinitramine.
abstract: Decomposition of γ-cyclotrimethylene trinitramine (γ-RDX) under high pressure-high temperature conditions was examined to elucidate the reactive behavior of RDX crystals. Vibrational spectroscopy measurements were obtained for single crystals in a diamond anvil cell (DAC) at pressures from 6 to 12 GPa and temperatures up to 600 K. Global decomposition rates, activation energies, and activation volumes at several pressures and temperatures below the P-T locus for the γ-RDX decomposition were obtained. Similar to ε-RDX, but in contrast to α-RDX, we found that pressure decelerates the decomposition of γ-RDX. The decomposition deceleration with pressure in the γ-phase can be attributed to pressure-inhibiting bond homolysis step(s). The main decomposition species were identified as N(2)O, CO(2), and H(2)O, in accord with the species reported for the α-phase decomposition at high pressures. This work complements previous studies on RDX at HP-HT conditions and provides comprehensive results on the reactive behavior of γ-RDX; the γ-phase plays a key role in RDX decomposition at P-T conditions relevant to shock wave initiation.
authors.affiliation: Institute for Shock Physics and Department of Physics, Washington State University, Pullman, Washington 99164-2816, USA. dreger@wsu.edu
authors.forename: Zbigniew A
authors.initials: ZA
authors.lastname: Dreger
authors.forename: Matthew D
authors.initials: MD
authors.lastname: McCluskey
authors.forename: Yogendra M
authors.initials: YM
authors.lastname: Gupta