Triplet energy transfer mechanism in isotopic mixed molecular crystals

Abstract

The transfer of triplet excitation energy between isotopic traps in benzene isotopic mixed crystals has been investigated using both steady-state and pulsed excitation sources. The prediction of the correct dependence of the transfer rate on trap depth by the excitation-tunneling transfer mechanism was demonstrated. It was shown that the Perrin approximation is a reasonable albeit not perfect approximation for this system. Using this approximation, it has been shown that the use of a linear-chain tunneling mechanism predicts the excitation exchange integral to be the correct magnitude. This conclusion is consistent with a strong distance dependence of the transfer rate constant. (BLM)