On the Evaluation of Kinetic Theory Collision Integrals: Diamagnetic Diatomic Molecules

A partial evaluation of the collision integrals for the Waldmann‐Snider collision superoperator is accomplished. This involves an exact integration over the center of mass coordinates and a distorted wave Born approximation treating the nonspherical part of the intermolecular potential as small. Certain exact relations between collision integrals are obtained after center of mass integration and further approximate relations are obtained within the DWB approximation. The general method of organizing the collision integrals has been considered according to their coupling $\text{(k ≠ 0)}$ of angular momentum and velocity directions and uncoupling (k=0). In particular, for the latter, approximate formulas are obtained for the j dependence of the relaxation cross sections. For all this work, the collision cross sections are expressed in terms of averages of the nonspherical potential over the collision dynamics due to the spherical potential.