Triple point of Yukawa systems

Abstract

The molecular dynamics simulations of Yukawa (i.e., screened-Coulomb) systems that were applied to the regime of weak screening in an earlier study [S. Hamaguchi, R. T. Farouki, and D. H. E. Dubin, J. Chem. Phys. 105, 7641 (1996)] are extended to the strong screening regime. Transition temperatures at the fluid-solid phase boundary and the solid-solid phase boundary are obtained as functions of the screening parameter [Formula Presented] (i.e., the ratio of the Wigner-Seitz radius [Formula Presented] to the Debye length [Formula Presented]). The resulting phase diagram also covers the triple point—the intersection of the fluid-solid and solid-solid phase boundaries—at [Formula Presented] and [Formula Presented] where Γ is the ratio of the Coulomb potential energy to the kinetic energy per particle (i.e., [Formula Presented] where [Formula Presented] is the charge of each Yukawa particle and [Formula Presented] is the system temperature). Yukawa systems serve as models for plasmas and colloidal suspensions of charged particulates. © 1997 The American Physical Society.