Series expansions for an electron–ion system

By means of finite-temperature, many-body perturbation theory we derive through order e4 the corrections to an ideal Fermi gas plus an ideal Maxwell–Boltzmann gas of ions. This computation is carried out for general values of the de Broglie density. In a previous paper we carried out this computation for the pressure. Here we extend it to the internal and potential energies, the chemical potential, Grüneisenʹs parameter, the adiabatic exponent, and the dimensionless specific heat. We discuss the limitations on our results and cross compare them with the results of the spherical cellular model.