Lennard-Jones Elastic Moduli by Liquid Structure Integral Equations and Molecular Dynamics Computer Simulations

Abstract

The infinite frequency shear modulus, G∞, and compressional modulus, K∞, of the Lennard-Jones, LJ, fluid have been determined over essentially the whole phase diagram at densities below the solid-fluid coexistence line using PY, HNC, and Rogers and Young (RY) closures of the Ornstein-Zernike relation. At low density PY is best at reproducing simulation G∞, and K∞, whereas close to the coexistence line, above the critical temperature, the RY closure is best and is remarkably accurate. Agreement is poorest for all three closures below T_c in the liquid phase.

Key Words:

• Shear and bulk infinite frequency modulus
• Lennard-Jones
• integral equations
• computer simulations