Monte Carlo simulations at constant pressure are used to characterize the structure of the restricted primitive model in the tetragonal-ordered solid phase. A method to estimate the location of the order-disorder transition and the densities of the coexistence phases is discussed. The results support the weakly first-order character of the transition.

• Received 31 July 2003

DOI:https://doi.org/10.1103/PhysRevE.68.052501