Relaxation of vibrational nonequilibrium distributions: the effect of multiphoton excitation on relaxation behavior

A theoretical study has been made on the non-stationary relaxation of highly vibrationally excited molecules in the presence of a source, producing these molecules. Initially, the nonequilibrium vibrational distribution is created using multiphoton absorption of laser radiation. An exact, analytical solution to the master equation is derived in terms of Meixner polynomials with regard to VV- and VT-processes. The time-dependent distribution of the system “molecule + field” is used to give explicit expressions for the mean number of photons distributed among vibrational and translational degrees of freedom and for the time dependence of average energy transferred per collision.