Thermodynamic state variables in quasiequilibrium ultracold neutral plasma.

The pressure and internal energy of an ultracold plasma in a state of quasiequilibrium are evaluated using classical molecular dynamics simulations. Coulomb collapse is avoided by modeling electron-ion interactions using an attractive Coulomb potential with a repulsive core. We present a method to separate the contribution of classical bound states, which form due to recombination, from the contribution of free charges when evaluating these thermodynamic state variables.