Kinetics of vibrational exchange in two-component gaseous mixtures in the presence of a resonant laser radiation field

Abstract

The kinetics of nonresonant vibration-vibrational (v-v) exchange in binary mixtures is considered in the presence of a laser field using the harmonic oscillator model and the approximation of single-quantum transitions. An integral representation is obtained for the distributions over the vibrational levels of each component making allowance for the v-v exchange, vibration-translational (v-T) relaxation, and influence of an infrared radiation source. A closed system of equations for the relaxation of the vibrational energy in the modes is derived ignoring the decay processes. The nonequilibrium distribution functions are obtained for the steady-state and quasisteady-state conditions. It is shown that if v1>v2 (v1 is the frequency of the mode excited by the laser field and v2 is the frequency of the mode to which the energy is transferred), the vibrational kinetics of a binary mixture may differ considerably from the kinetics of a single-component medium provided that the strong laser, field acts on the first component and the rate of exchange of the quanta between the modes under consideration is sufficiently rapid. This circumstance makes it possible to utilize a directional v-v exchange for the purpose of efficient heating of a mode with a lower vibrational energy. The conditions under which this occurs are determined.