Real-time X-Ray diffraction measurements of the phase transition in KCl shocked along

X-ray diffraction measurements and analyses were developed and used to examine the phase transition in KCl shocked to 7 GPa. Diffraction data were obtained below and above the transition stress, and related quantitatively to macroscopic compression in the two phases. Interplanar spacing measurements revealed isotropic compression of the unit cell. Above the transition stress, a diffraction peak from the (110) planes in phase II was observed consistently and the orientation of the transformed crystal structure was determined with respect to the phase I structure. This determination provides a mechanism for the atomic rearrangement from the rocksalt to the cesium chloride structure in KCl shocked along [100].