Abstract: | The influence of the classical polar medium fluctuation on the nonradiative transition rate in molecules is considered. Change of the vibrational frequencies under electron excitation is taken into account. In the Gauss–Markov approximation for the fluctuation and the linear model of the vibrational term of the final electronic state, the formula for the rate of the process at low temperature is obtained. The formula reveals the temperature dependence arising from the influence of the environment medium on the barrier of the reaction. The theory is applied to the explanation of the value and temperature dependence of the rate of the low‐potential cytochrome oxidation. ©1999 John Wiley & Sons, Inc. Int J Quant Chem 74: 381–386, 1999 |