Radiationless Intermolecular Energy Transfer. IV. Triplet—Triplet Annihilation

Abstract

Phosphorescence quenching for phenanthrene-d10 has been observed in solid solution. The quenching efficiency is dependent on the triplet concentration ηT with a threshold at ηT∼10—3 M. It is interpreted to occur by the process T1+T1→S0+T2, involving a radiationless transfer of one triplet excitation to the triplet—triplet absorption band of the other. The necessary conditions described by Förster for dipole—dipole radiationless energy transfer are shown to be satisfied.