Non-radiative transitions in the oscillating field model

The model of energy levels crossing in the theory of non-radiative transitions (NRT) has been developed. In the framework of this model NRT are due to the crossing of purely electron energy states of the impurity ion caused by ligands thermal vibrations. Analytical expressions describing the temperature dependence of the NRT probabilities are obtained. The results of calculation of the 3T2→3A2 NRT for the tetrahedrally coordinated Cr4+ ion are reported. An accordance between the theoretical calculations and experimental data is discussed.