The Pauli principle and the restricted primitive model

The restricted primitive model is an electrically neutral, classical model consisting of hard spheres charged either +q or -q. We show that, by approp riately selecting the diameter of the hard spheres, the pressure when q = 0 can be made equal to that for a fluid of Maxwell-Boltzmann point ions and an ideal Fermi gas of electrons. We compare the series expansion of these c lassical and quantum systems and find that, except for intermediate de Brog lie density and moderate to strong electrical interaction strength, the res tricted primitive model gives a reasonable representation of the pressure o f the corresponding quantum system, Much of the current interest, however, has been focused on the above, excepted region.