Transport Properties of a Gas of Diatomic Molecules

Abstract

Explicit expressions, valid in the classical limit, are derived for the rotational relaxation time and viscosity of a low‐density gas of rotating, nonvibrating, diatomic molecules. These expressions are based on the quantum mechanical expressions in terms of the degeneracy‐averaged cross sections for a gas in which the average angular momentum of the molecules is zero. The use of an expression for the classical limit of the degeneracy‐averaged cross section leads to the evaluation of several of the summations and integrations.