Electronic Energy Radiationless Transition as Radiationless Dipole-Dipole Energy Transfer to Vibrations of Solvent Molecules

Abstract

The main cause of the degradation of electronic excitation energy in rare-earth and transition metal ions is shown to he an inductive-resonance dipole-dipole energy transfer from excited ions to the solvent vibration overtones. The suggested mechanism can quantitatively explain such regularities as: 1. the linear dependence of log k_degr. on ΔE, and the causes of deviation from linearity; 2. deuteriun influence upon k_degr.; 3. existence of spin forbiddenness for radiationless transitions; and 4. dependence of k_degr. on distance between the excited ions and the nearest high frequency vibration groups of the solvent. It is shown that this mechanism of energy degradation holds equally well for any aggregate state: liquid, glass and crystal.