Triple point of Yukawa systems

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 =a/₃ (i. e. , the ratio of the Wigner-Seitz radius a to the Debye length ₃). The resulting phase diagram also covers the triple point---the intersection of the fluid-solid and solid-solid phase boundaries---at =4. 28 and =5. 610^3, where is the ratio of the Coulomb potential energy to the kinetic energy per particle (i. e. , =Q^2/4₀akT, where Q is the charge of each Yukawa particle and T is the system temperature). Yukawa systems serve as models for plasmas and colloidal suspensions of charged particulates.