On the index of refraction of shock-compressed liquid nitromethane

The index of refraction of shock-compressed liquid nitromethane has been determined from 7.5 to 9.5 GPa. These data were obtained under the condition of one-dimensional compression in the liquid in the course of powder gun projectile impact studies of the shock initiation of the liquid explosive. Diagnostic information obtained by means of streak camera photography and velocity interferometry was compared with previously obtained equation-of-state information in order to evaluate the refractive index of the shocked liquid prior to the onset of chemical decomposition. Our results suggest the validity of the Gladstone-Dale relationship for the prediction of the density dependence of the index of refraction of nitromethane at pressures in the range 5–10 GPa.