Ruby R-line shifts for shock compression along (1102)

Abstract

Experimental measurements of the shifts of ruby R lines, for shock loading along the low symmetry r direction, were obtained to evaluate our earlier theoretical formulation regarding the response of R lines in ruby crystals subjected to arbitrary deformations. The experimental results show good agreement with the calculated values based on symmetry adapted irreducible strains and, therefore, make a strong case for the predictive capability of the theoretical model. Additionally, the parameters in the theory were augmented to incorporate the previously observed nonlinear shifts of the R lines for shock compression along the c and a axis. With the general validation of our theoretical model, oriented ruby chips can now be utilized in diamond anvil cell experiments to obtain quantitative estimates of stress deviators at high pressures. These, in turn, can be used to evaluate material strength, and the role of nonhydrostatic stresses on sample response, at large compressions.