Scaling of Lennard–Jones liquid elastic moduli, viscoelasticity and other properties along fluid–solid coexistence

Abstract

AbstractStatic and dynamical properties of the Lennard–Jones (LJ) fluid along the fluid–solid coexistence line are determined by molecular dynamics simulation. A number of properties, such as the radial distribution function, Einstein frequency, mean force, root mean square force, and normalised time correlation functions are shown to be essentially invariant or structurally isomorphic along this line when scaled by so‐called macroscopic variables (MRU). Other quantities subject to MRU such as the potential energy, pressure and infinite frequency compressional modulus are not constant along this line of states but can be reproduced using simple formulae of the form for Roskilde fluids. The elastic moduli fall within the domain of isomorphism theory. A generalised Cauchy relationship in which the infinite frequency longitudinal modulus is proportional to the longitudinal modulus of the fluid was found to be obeyed very well for the LJ fluid phase along this coexistence line.