Rotational Relaxation of Homonuclear Diatomic Molecules

Through the use of Wang Chang and Uhlenbeck's theory of polyatomic gases, rotational relaxation times for homonuclear diatomic molecules have been calculated. The model adopted is that of two molecules rotating in the same plane which also serves as the collision plane. The intermolecular potential used is Parker's modification of the Morse potential, where the molecular orientations are taken into account only in the repulsive part. This leads to a relaxation time, for which the ``collision number'' Zrot is essentially independent of temperature. Owing to the lack of any experimental information concerning the temperature dependence of rotational relaxation the discussion has been limited to a few comments about earlier calculations.