Effect of the pumping level on the dynamics of establishing the distribution of diatomic molecules over vibrational levels

Abstract

Strong vibrational nonuniformity is achieved relatively easily for a number of molecules, for example, in a gas discharge or in the case of optical excitation. This nonuniformity can be used in molecular lasers (for example, a CO laser) as well as for carrying out chemical reactions. The problem of finding a vibrational distribution function under conditions of strong excitation has been solved in many papers (for example, see the review [1]) in large part numerically. An approximate analytic theory which permits finding the steady distribution function was constructed in [2–4]. Approximate analytic solutions of the problem of establishing the vibrational distribution function under conditions of variable pumping have been found in [5], and the applicability of the solutions obtained for the description of physical reality in the case of sufficiently powerful pumping is demonstrated. The purpose of this paper is to clarify the lower limit with respect to pumping power of the applicability of the theory of [5], The evolution of the distribution function over the vibrational levels in nitrogen is considered as an example.