Pressure dependence of electronic relaxation: A stochastic model

Abstract

We have constructed an exactly solvable stochastic model describing the pressure dependence of electronic relaxation processes in polyatomic molecules. From it closed‐form algebraic expressions for time resolved emission intensities and quantum yields are extracted. Fundamental to this model are (1) a variation of the radiative and nonradiative decay rates of the electronic state with vibrational excitation within that state and (2) a ``step‐ladder'' collisional dynamics scheme similar in nature to those investigated by Montroll and Shuler and applied to diatomic molecules. We describe how this model can be used to obtain estimates of the average variation of the radiative and nonradiative decay rates with excess vibrational energy as well as the average vibrational energy transferred per vibrationally inelastic collision and the rate for this energy transfer process. Furthermore, the model suggests physical situations in which ``nonexponential'' electronic relaxation can be expected to be observed.