Microscopic Experimental Approaches to High Pressure Chemistry

Abstract
The experimental study of the chemistry related to the deflagration/detonation of energetic materials is extremely challenging due to the high pressure, high temperature, and time domain under which the chemical reactions occur. In addition, non equilibrium pressure and temperature conditions temporally effect the reaction pathways and rates during the reaction process. The multiple phases of material present (i.e. the heterogeneous nature of the problem), the multiple reaction pathways (both in series and in parallel), and the temporal dependency of the physical conditions make the assignments of the early reaction products, product sequence, and reaction mechanism an extremely difficult if not nearly unsolvable problem. Recently, experimental approaches have been developed which permit the spectroscopic identification of products species, reaction sequences, and global reaction rates under simulated detonation conditions. Three experimental techniques : (1) high pressure matrix isolation (2) high pressure time-resolved absorption spectroscopy , and (3) high pressure time-resolved emission spectroscopy are used in conjunction with a gem anvil cell to probe the high pressure chemical processes.