Equation of state of dense plasmas using a screened-hydrogenic model with ℓ-splitting

We present a self-consistent model based on a nonrelativistic screened-hydrogenic model with ℓ-splitting to calculate the equation of state of matter in local thermodynamic equilibrium. We take into account the quantum subshell effect to go beyond the simple semiclassical and statistical Thomas–Fermi approach to obtain the electronic properties. Arbitrary degeneracy is allowed for the free electrons. Pressure ionization mechanism, which plays a key role in the present ionization-equilibrium model, is carefully described. Ion properties and cold curve are determined using the QEOS multiphase equation of state. The whole model is fast, robust, and reasonably accurate over a wide range of temperatures and densities.