Transport properties of homonuclear diatomics

Abstract

The molecular dynamics technique has been used to calculate certain time-correlation functions which occur in the transport theory of fluids composed of rigid molecules. These correlation functions are the Green-Kubo integrands of the following hydrodynamic transport coefficients: thermal conductivity, shear, bulk and vortex viscosity, and the corresponding spin viscosities. The calculations were carried out for liquid nitrogen (pressure essentially zero and temperature 78 K) modelled by a diatomic Lennard-Jones potential. For the transport coefficients supported by experimental data, agreement between calculated and experimental values is good. Our calculations predict a highly non-exponential Green-Kubo integrand for vortex viscosity. They also suggest limits at which breakdown can be expected in the conventional Navier-Stokes equation characterizing macroscopic flow of liquid nitrogen.