Effect of laser radiation on the vibrational distribution of CO₂

Abstract

In connection with progress in the field of CO₂ lasers, questions of the vibrational kinetics of molecules of CO₂ have been discussed in many communications. In a majority of cases of practical importance, the distribution of CO₂ is due to processes of vibrational exchange (V-V) on which is based the well-known thermodynamic model [1]. In other cases, the V-V exchange does not determine the vibrational distribution, since the perturbation is small; therefore, it is found sufficient to consider a small number of levels of CO₂ (usually three), whose populations satisfy the linear equations of the balance [2]. There is the possibility of conditions where the vibrations are strongly excited and, at the same time, V-V processes are insignificant (a very small CO₂ impurity in the inert gas, with a high degree of ionization). Then the number of equations becomes large. The present article discusses one such case: the excitation of a steady-state vibrational distribution in a glow discharge by laser radiation, whose solution is rather graphic.