Electronic conduction in shock-compressed water

The optical reflectance of a strong shock front in water, which increases with pressure above 100 GPa, was discussed. The water Hugoniot equation of state up to 790 GPa was also determined. The shock velocity measurements, made by detecting the Doppler shift of reflected light, were used for the purpose. It was found from a fit to the reflectance data, that an electronic mobility gap ∼2.5 eV controls thermal activation of electronic carriers at pressures in the range of 100-150 GPa. The results show that above 150 GPa, electronic conduction contributes significantly to the total conductivity along the Neptune isentrope.