On the theory of vibrational relaxation of diatomic molecules

The relaxation of diatomic molecules (harmonic oscillators) in a relatively light inert gas, which plays the part of a thermostat, is considered within the framework of classical mechanics. The gas-kinetic equation for the distribution function of diatomic molecules is approximated by the Fokker-Planck equation in the space of the energies of translational, rotational and vibrational motions on the assumption of strong nonadiabaticity of the collisions. In the approximation discussed, relaxation processes with different degrees of freedom develop independently, although the characteristic times of these processes are quantities of the same order. The vibrational relaxation time, expressed in terms of the gas-kinetic integral ^*(1,1) (T*), is obtained.