Triplet-Triplet Energy Transfer between Like Molecules

The previously proposed method of studying T-T energy trasfer between like molecules using isotopic mixtures was further improved and applied to an investigation of naphthalene and phenanthrene molecules. Critical transfer distances of 15 and 13 A were determined for naphthalene and phenanthrene, respectively. The present method has the advantage that it is free from the effect of S-S energy transfer.