Platinum equation of state to greater than two terapascals: Experimental data and analytical models

Abstract

In order to develop a high impedance standard for shock physics applications, we investigated the equation of state (EOS) and shock compression of bulk platinum using canonical ab initio molecular dynamics (AIMD) simulations, coupled with experimental data on Sandia's Z machine. In simulations, we sampled the thermodynamic state space along isotherms ranging from 300 to 100 000 K for densities of 18 to 40 $\mathrm{g}/{\mathrm{cm}}^{3}$. While this rectilinear grid of EOS points was useful for preliminary experimental design, material going outside of the density/temperature space of the AIMD simulations required a SESAME-style, broad-range EOS, which we developed independently and subsequently compared to the AIMD simulations. In the final step we validated the SESAME EOS with experimental shock data to 2177 GPa on Sandia's Z machine. The theoretical and AIMD results are in excellent agreement with experiments.