A determination of the ruby high-pressure scale is presented using all available appropriate measurements including our own. Calibration data extend to 150 GPa. A careful consideration of shock-wave-reduced isotherms is given, including corrections for material strength. The data are fitted to the calibration equation P = ͑A / B͓͒͑ / 0 ͒ B −1͔ ͑GPa͒, with A = 1876± 6.7, B = 10.71± 0.14, and is the peak wavelength of the ruby R1 line.

Dynamic equation-of-state data for liquid CO and CH4 were measured in the shock pressure range 5–92 GPa (50–920 kbar) using a two-stage light-gas gun. The liquids were shocked from initial states near their saturation curves at 77 and 111 K for CO and CH4, respectively. The experimental technique used to double-shock CH4 is described. The CO data were examined by using three theoretical models: (1) a chemically nonreactive model, (2) a quasi-chemical-equilibrium model that allows CO to dissociate into gaseous species and graphite, and (3) a chemical-equilibrium model that also includes a dense carbon phase which exists at higher pressures and temperatures than graphite. This dense phase is assumed to be diamond. Our analysis shows that at low pressure chemical equilibrium takes much longer than a typical shock passage time. As a consequence, the experimental data initially follow the nonreactive Hugoniot to pressures well beyond the chemical dissociation limit. Both the experimental data and the Hugoniot computed with case (3) agree satisfactorily at high pressure. Further consequences of these observations to high-explosive studies are discussed. The theoretical analysis for the CH4 data was presented in an earlier paper.

Equation-of-state data were measured for liquid carbon dioxide and air shock-compressed to pressures in the range 28-71 GPa (280-710 kbar) using a two-stage light-gas gun. The experimental methods are described. The data indicate that shock-compressed liquid CO, decomposes at pressures above 34 GPa. Liquid air dissociates above a comparable shock pressure, as does liquid nitrogen. Theoretical intermolecular potentials are derived for CO, from the data. The calculated shock temperature for the onset of CO, decomposition is 4500 K at a volume of 17 cm3/mo1. ' 1. GPa = 10 kbar.

Off-Hugoniot equation-of-state (EOS) measurements were performed on Al, Cu, and Ta shocked to pressures in the range 62–430 GPa and double-shocked or released isentropically to pressures in the range 80–440 GPa. Calculated temperatures of the off-Hugoniot states are in the range 2 400–14 500 K. All these off-Hugoniot data are in good agreement with approximating the double-shock and isentropic release curves with the mirror reflection in P−up space of the principal Hugoniot about the vertical axis through particle velocity up1 of the first-shock state. Effective Grüneisen γ’s of Al are in good agreement with the scaling relationship γ=γ0(V/V0). The high accuracy of EOS data of Al, Cu, and Ta, both on and off the principal Hugoniot, and their simple behaviors, including the absence of any observed phase transitions, qualifies these metals as EOS standards for use as anvils in shock-compression experiments.

Shock temperature measurements have been performed on several materials which have relevance to the modeling of the outer planets. These materials are methane, ammonia and a mixture of water, ammonia, and isopropanol known as synthetic Uranus. Temperatures have been measured in these materials over the pressure range 33–76 GPa for which there also exists measurements of equation of state and electrical conductivity. The temperatures are found to agree well with available calculations, with small discrepancies between data and theory ascribed to energy absorbing processes such as dissociation and molecular ionization.

High-pressure shock Hugoniot data were measured for Be using strong shock waves generated by underground nuclear explosions. These data and a preliminary theoretical analysis are reported.

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The electrical resistivity of single-crystal Al2O3 was measured at shock pressures in the range 91–220 GPa. Shock pressures were generated by impacts of hypervelocity projectiles accelerated with a two-stage light-gas gun. The resistivity varied from 170 to 20 Ω cm in the pressure range 91–180 GPa and then rapidly decreased to 0.2 Ω cm at 220 GPa.