title: Order-disorder transition in the solid phase of a charged hard sphere model.
abstract: We investigate the solid phases of the restricted primitive model (RPM). Monte Carlo simulations show the existence of an order-disorder transition from a substitutionally disordered face centered cubic lattice (fcc) to a new ordered fcc structure which is proposed as the ground state of the RPM at the close packing density. Our results suggest that the new phase might turn out in a new triple point in the RPM phase diagram involving three solid phases: CsCl, fcc ordered and fcc disordered structures. The order-disorder transition is also studied using the cell theory. The theory shows good agreement with the simulation results and suggests that the transition is weakly first order.
authors.affiliation: Department of Chemistry, Imperial College of Science, Technology and Medicine, Exhibition Road, London SW7 2AY, United Kingdom.
authors.forename: F
authors.initials: F
authors.lastname: Bresme
authors.forename: C
authors.initials: C
authors.lastname: Vega
authors.forename: J L
authors.initials: JL
authors.lastname: Abascal