A semi-empirical iron EOS for temperature predictions in high pressure shock-ramp experiments

Experiments to determine the multi-Mbar melt temperature of iron through the identification of high pressure solidification are underway. While these measurements are aided by in situ X-ray diffraction, the temperatures in the final ramped states are unconstrained at present. With the regime of P = 2 – 14 Mbar and T= 2000 – 12000 K in mind, we construct a multiphase Fe EOS from a combination of static and dynamic experimental data, together with simple models for single-phase free energies informed by DFT-based molecular dynamics studies. Temperature predictions for the recent shock-ramp experiments using this EOS will be discussed, as well as the sensitivities of these predictions to various choices in the EOS model construction.