Molecular Dynamics Calculation of the Viscosity of Xenon Gas

The density variation of the viscosity of xenon gas is determined using molecular dynamics simulation with a semi-empirical pair potential fit to low-density gas properties. The gas states ranged in density from 0.37 to 7.62 mol · dm⁻³, and varied in temperature from 240 −591 K. The simulation results match the kinetic-theory predictions for the model potential at the lowest density, and systematically lie below the experimental values for higher densities. This indicates the need for many-body interactions to accurately predict the viscosity of xenon gas at even moderate densities. An operational criterion for identifying the density region where kinetic theory is appropriate is proposed.