Consideration of intermolecular energy exchange in describing relaxation processes in terms of adiabatic variables

Two methods of describing the contribution of intermolecular energy exchange to the relaxation of individual level populations in terms of adiabatic variables are examined. One method is based on the use of the 'effective' probabilities of inelastic transitions, while the other method relies on the symmetrization of the equations for energy level populations. The advantages and disadvantages of the two methods are discussed. Both methods make it possible to obtain approximate analytical solutions of the kinetic equations for different relaxation regimes.