Double energy transfer in rigid glass

Abstract

The occurrence of two successive energy transfers between two molecules (double energy transfer) has been shown in the phosphorescence from ethanol containing phenanthrene and 1-bromonaphthalene. Both the phosphorescence rise and decay curves of phenanthrene have been observed to consist of rapid and slow components when the wavelength of the excitation light is short enough to be absorbed by 1-bromonaphthalene. On the contrary, the rapid components of the rise and decay curves have been observed to disappear when the excitation light is absorbed by phenanthrene alone. A simple kinetic model has been proposed which can explain the experimental results consistently. The rapid components of the rise and decay curves have been ascribed to the triplet–triplet energy transfer enhanced by the singlet–singlet energy transfer.