Order-disorder transition in the solid phase of a
charged hard sphere model
Fernando Bresme, Carlos Vega and José L.F. Abascal
Physical Review Letters 85, 3217-3220 (2000)
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[DOI]
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.
