Investigation of Triplet-State Energy Transfer in Organic Single Crystals by Magnetic Resonance Methods

Abstract

The transfer of triplet‐state energy from phenanthrene‐d₁₀ molecules to naphthalene molecules in a single crystal of diphenyl has been investigated by electron magnetic resonance methods. The decay rates of the magnetic resonance signals of triplet‐state phenanthrene‐d₁₀ and naphthalene, both when they occurred as single solutes and also when they occurred together in diphenyl single crystals, have been studied over a wide range of temperatures. A number of processes leading to a satisfactory kinetic model have been considered and numerical values of concentrations of postulated species and of rates have been determined. Predictions concerning delayed optical emission, made on the basis of the proposed kinetic model, have been experimentally confirmed.