A comparison of scattering angle models

In Monte Carlo calculations of rarefied gas flows, physical interaction potential models are often replaced by computationally more efficient phenomenological models for the scattering angle in a binary collision. In this paper, the Variable Hard Sphere, Variable Soft Sphere and M1 computational scattering angle models are compared amongst themselves and with several physical potentials. Comparisons are given for the scattering angle as a function of impact parameter and for the ratio of the diffusion coefficient to the viscosity coefficient.