High-Pressure Behavior of Precompressed CO2 Shocked to ~10 Mbar

CO2 is present in the atmospheres and interiors of Jovian planets, atmospheres of exoplanets,and within Jovian moons. To study the high-pressure behavior of CO2, we used laser-driven shocks to compress CO2 to ~1 TPa (10 Mbar). The CO2 was precompressed in diamond-anvil cells to 5 kbar, producuing liquid at density (~1.5 g/cm3), and then shocked by the OMEGA Laser System. Equation of state, temperature, optical reflectivity, and heat capacity were measured between 150 and 950 GPa. CO2 undergoes an insulator-to-conductor transition above 200 GPa, which may be the result from dissociation to metallic oxygen. These data can add to the understanding of thermochemical histories of the giant planets. This material is based upon work supported by the Department of Energy National Nuclear Security Administration under