On the Theory of Nonradiative Transitions in Polar Media I. Processes without “Mixing” of Quantum and Classical Degrees of Freedom

The probability of radiationless transitions between two multi‐dimensional parabolic terms is calculated. The dependence of transition probability on temperature and heat of the processes is investigated. It is shown that all the degrees of freedom of the system may be divided into “classical” and “quantum” degrees of freedom in dependence of their behaviour during process. The activation dependence of the transition probability on the temperature is associated with the motion along the classical degrees of freedom only. The change of states of quantum degrees of freedom leads to the appearance of an exponential non‐temperature factor in the transition probability. The transition is shown to be of activationless or barrierless character at large values (modulo) of the heat of process for the processes without “mixing” of classical and quantum degrees of freedom.