A study of transient processes in unimolecular reactions within the framework of the modified exponential model of the collisional transition probability density

A new model of the exponential type for describing the collisional transition probability density for an energy-dependent collision cross section is developed. This model satisfies the requirements of detailed balance and normalization in the energy interval (0...+infinity) and makes it possible to perform a gradual transition from the diffusion to the strong-collision regime by varying a single adjustable parameter. This :model is used to analyze the master equation for the N2O molecule; the relaxation and dissociation rates, the duration of the incubation period, and the time required to reach the steady-state distribution near the dissociation barrier are calculated. The applicability of the Wentzel-Kramers-Brillouin method to a simplified analysis of the master equation for eigenvalues is demonstrated.