Order-Disorder Transition in the Solid Phase of a Charged Hard Sphere Model

Fernando Bresme; Carlos Vega; José L. F. Abascal

doi:10.1103/PhysRevLett.85.3217

Order-Disorder Transition in the Solid Phase of a Charged Hard Sphere Model

Fernando Bresme, Carlos Vega, and José L. F. Abascal

Phys. Rev. Lett. 85, 3217 – Published 9 October 2000

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.

Received 2 March 2000

DOI:https://doi.org/10.1103/PhysRevLett.85.3217

Authors & Affiliations

Fernando Bresme¹, Carlos Vega², and José L. F. Abascal²

¹Department of Chemistry, Imperial College of Science, Technology and Medicine, Exhibition Road, London SW7 2AY, United Kingdom
²Departamento de Química-Física I, Facultad de CC. Químicas, Universidad Complutense de Madrid, E-28040 Madrid, Spain