Vibrational energy dependence of nonradiative decay rate: Triplet benzene studied by time-resolved and steady-state photosensitized phosphorescence Original Research Article

The nonradiative decay rate of triplet benzene was determined as a function of excitation energy utilizing the phosphorescence of biacetyl induced by the energy transfer from triplet benzene. The triplet benzene was formed by intersystem crossing from the photoexcited singlet molecule. The nonradiative decay rate determined by combination of time-resolved and steady-state measurements increased from 8.5 × 103 s−1 to 4 × 106 s−1 as the excitation energy was varied from 38000 to 41000 cm−1, i.e. 8500 to 11500 cm−1 excess vibrational energy in the triplet state. The increasing trends were in reasonable agreement with previously reported experimental results and also with theoretical calculations.