Time correlation functions and transport coefficients of two-dimensional Yukawa liquids

TL;DR

This study investigates the existence of transport coefficients like diffusion, viscosity, and thermal conductivity in 2D Yukawa liquids through molecular dynamics simulations, revealing temperature-dependent behaviors and methodological improvements.

Contribution

The paper introduces enhanced simulation methods and larger system sizes to better assess transport coefficients in 2D Yukawa liquids, clarifying their existence across temperature ranges.

Findings

Diffusion coefficient exists at high temperature.

Viscosity coefficient exists at low temperature.

Thermal conductivity coefficient does not exist at high temperature.

Abstract

The existence of coefficients for diffusion, viscosity and thermal conductivity is examined for two-dimensional (2D) liquids. Equilibrium molecular dynamics simulations are performed using a Yukawa potential, and the long-time behavior of autocorrelation functions is tested. Advances reported here as compared to previous 2D Yukawa liquid simulations include an assessment of the thermal conductivity, using a larger system size to allow meaningful examination of longer times, and development of improved analysis methods. We find that the transport coefficient exists for diffusion at high temperature, and viscosity at low temperature, but not in the opposite limits. The thermal conductivity coefficient does not appear to exist at high temperature. Further advances in computing power could improve these assessments by allowing even larger system sizes and longer time series.