Phosphorescence Decay Kinetics in the Presence of Statistical Distribution of Molecules Over the Rates of Radiative and Nonradiative Deactivation of Triplet Excitations

Approximate formulas of the phosphorescence decay kinetics have been obtained for the statistical distribution of molecules over the rate constants of radiative and non-radiative deactivations of triplet excitations. It is shown that the characters of the phosphorescence decay differ for these two cases. The obtained difference in the kinetics has been used to establish a reason for the deviation from the exponential law and a faster decay of the sensitized phosphorescence of naphthalene and diphenyl in n-paraffin matrices (at T = 77 K) in the presence of heavy dibromo-diphenylene sulfide atoms in the donor.