The equation of state (EOS) serves an essential input for many scientific explorations, including geophysics and planetary studies and hydro-simulations of inertial confinement fusion experiments. One key component of an EOS is the compressibility curve of the material of interest, which is often computed by first principles methods or determined by diamond-anvil-cell (DAC) experiments with the usage of a pressure scale. The need for reliable pressure scales becomes particularly important at high pressure (P > 2 Mbar) when many existing pressure scales differ significantly. In this talk we present our recent work on the development of EOSs for several materials widely used as pressure scales. We will discuss the accuracy of pressure scales from the EOS theory perspective, as well as the connection between static, ramp and shock experiments which depend also on the magnitude of thermal components.

This work was carried out under the auspices of the US Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.