Thermodynamics of two-dimensional Yukawa systems across coupling regimes

Abstract

Thermodynamics of two-dimensional Yukawa (screened Coulomb or Debye-Hückel) systems is studied systematically using molecular dynamics (MD) simulations. Simulations cover very broad parameter range spanning from weakly coupled gaseous states to strongly coupled fluid and crystalline states. Important thermodynamic quantities, such as internal energy and pressure, are obtained and accurate physically motivated fits are proposed. This allows us to put forward simple practical expressions to describe thermodynamic properties of two-dimensional Yukawa systems. For crystals, in addition to numerical simulations, the recently developed shortest-graph interpolation method is applied to describe pair correlations and hence thermodynamic properties. It is shown that the finite-temperature effects can be accounted for by using simple correction of peaks in the pair correlation function. The corresponding correction coefficients are evaluated using MD simulation. The relevance of the obtained results in the context of colloidal systems, complex (dusty) plasmas, and ions absorbed to interfaces in electrolytes is pointed out.

Collective modes of two-dimensional classical Coulomb fluids

“…This functional form has been proven to be very useful for various fluids characterized by soft long-ranged interactions in 2D. 31,32,88,89 Appendix B: Simplified expressions for L and T The explicit expressions for L(k) and T (k) for the 2D Coulomb system are 21,55 L 2 (k) = ω 2 0 q + ω 2 0 ∞ 0 h(x) 2x 2 [1 − J 0 (qx) + 3J 2 (qx)] dx,…”

“…Another purpose of the present work is to put the 2D Coulomb system in the context of other classical soft interacting particles in 2D geometry. In a series of papers we have reported detailed investigation of thermodynamics and dynamics of several classical systems of soft-interacting particles in 2D, such as one-component plasma (characterized by logarithmic interaction between the particles), 29,30 Yukawa systems, 31 and dipole-like systems (with ∝ r −3 interaction). 32 Present work represents a logical continuation of these studies.…”

High-frequency elastic moduli of two-dimensional Yukawa fluids and solids

“…The latter has been evaluated previously. 13,21,51 The results can be conveniently fitted by the expression 21 M = −1.1061 + 0.5038κ − 0.11053κ 2 + 0.00968κ 3 + 1 κ .…”

“…[7][8][9] Many studies have previously addressed important topic related to the thermodynamics and dynamics of 2D Yukawa crystals and fluids. [10][11][12][13][14][15][16][17][18][19][20][21] Most of these studies considered only one phase (either crystal or fluid). The purpose of this work is to present a physically motivated unified approach to evaluate elastic moduli and related properties of 2D Yukawa systems, which represents a good approximation in the strongly coupled fluid regime and becomes exact in the limit of an ideal crystalline lattice.…”

Thermodynamics and dynamics of two-dimensional systems with dipolelike repulsive interactions

“…In particular, the Rosenfeld-Tarrazona (RT) scaling [59,60] of the thermal component of the internal excess energy on approaching the freezing transition allowed previously to construct a very simple practical approach to the thermodynamics of weakly screened Yukawa systems in 3D [61][62][63]. An analog of the RT scaling also exists in the 2D case (although of a quite different functional form) and this has been recently used to construct a simple thermodynamic description of one-component plasmas and weakly screened Yukawa systems in 2D [64][65][66][67] with main applications to complex (dusty) plasmas. Here we apply the same arguments to the 2D system with 1/r 3 dipolar interactions to put forward simple and accurate expressions for the thermodynamic properties of the liquid state, which are (by construction) in excellent agreement with the MD simulation results.…”