Wide-ranged equation of state models for elements from the atom-in-jellium approach*

We discuss the construction of wide-ranged equation of state models for elements using a DFT-based average-atom model. In our approach, high pressure cold, ion-thermal, and electron-thermal contributions of the free energy are all created from the atom-in-jellium paradigm. In particular, the ionic excitation piece is constructed by computing the restoring force to small displacements of the nucleus within a neutral spherical jellium cell, and the Lindemann criterion is adopted to predict the density-dependent melt curve. We show that with a minimum of fitting to low pressure experimental data (e.g., ambient density, melt temperature at ambient pressure), remarkably accurate wide-ranged equations of state can be generated using this method, as demonstrated by comparing to high pressure experimental data and more sophisticated ab initio predictions.