Identifying liquidlike and gaslike states of dusty plasmas using isomorph theory

Equilibrium molecular dynamical simulations are performed to investigate the isomorphic properties of the supercritical liquidlike to gaslike transition in Yukawa fluids. From the calculated Pearson correlation coefficient R , the isomorph theory is always applicable in both the liquidlike and gaslike states of Yukawa systems, so that the Frenkel line is also an isomorphic curve, as discussed here. Based on the isomorph theory, it is proposed that the height of the first peak of the radial distribution function g ( r fp ) can be used as a convenient and sensitive criterion of the Frenkel line, which is g ( r fp ) = 1.2 for two-dimensional and g ( r fp ) = 1.14 for three-dimensional Yukawa fluids. This criterion of the Frenkel line from g ( r fp ) well agrees with the widely accepted condition of C T / v th = 2 for the supercritical transition, as well as the equivalent of the reduced instantaneous shear modulus G ∞ / n k B T = 2 . The criterion of g ( r fp ) provides a convenient method to identify the supercritical transition of dusty plasmas or Yukawa fluids, which may be extended to other physical systems.