Multiphase EOS Table for Gallium*

We developed the first LLNL multiphase equation of state (EOS) for Gallium (Ga) covering a wide range of density (10^-7-10³ g/cc) and temperature (1-10⁹K). The EOS includes three known solid phases (I, II and III) and one Ga liquid. The EOS table accurately reproduces available experimental Hugoniot, isotherms and isobar data, as well as observed phase boundaries. We demonstrate that there is a significant uncertainty in predicted phase boundaries beyond the range of existing experimental observations, since they are highly sensitive to small changes in the free energy differences between the neighboring phases. EOS model uncertainty and variations will also be explored in this study.