Shock Compression of Strongly-Correlated Oxides: A Liquid-Regime Equation of State for Cerium(IV) Oxide

The shock Hugoniot for full-density and porous CeO₂ was investigated in the liquid regime using ab initio molecular dynamics (AIMD) simulations with Erpenbeck's approach based on the Rankine-Hugoniot jump conditions. The phase space was sampled by carrying out NVT simulations for isotherms between 6,000 and 100,000 K and densities ranging from ρ = 2.5 to 20 g/cm³. The impact of on-site Coulomb interaction corrections +U on the EOS obtained from AIMD simulations was also assessed by comparison with standard DFT results. Results from dynamic compression simulations compare favorably with recent Z-machine shock data to 525 GPa and gas-gun data to 109 GPa for porous CeO₂ samples.