Observations of shock-induced reaction in liquid bromoform up to 11 GPa

Shock measurements on bromoform (CHBr3) over the past 33 years at Los Alamos have led to speculation that this material undergoes a shock-induced reaction. Ramsay observed that it became opaque after a 1 to 2 μs induction time when shocked to pressures above 6 GPa (1). McQueen and Isaak observed that it is a strong light emitter above 25 GPa (2). Hugoniot data start to deviate from the anticipated liquid Hugoniot at pressures above 10 GPa. We have used electromagnetic particle velocity gauging to measure wave profiles in shocked liquid bromoform. At pressures below 9 GPa, there is no mechanical evidence of reaction. At a pressure slightly above 10 GPa, the observed wave profiles are similar to those observed in initiating liquid explosives such as nitromethane. Their characteristics are completely different from the two-wave structures observed in shocked liquids where the products are more dense than the reactants. As with explosives, a reaction producing products which are less dense than the reactants ...