Lifetimes and Diffusion of Singlet Excitons in Naphthalene Crystals

概要

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Fluorescence decay times of naphthalene crystals were observed pulsively and their temperature dependence was analyzed with a mechanism of violated forbidden transition by molecular vibration. Fluorescence decay times of anthracene and naphthacene doped crystals were also observed by a pulsive method and the probabilities of energy transfer from singlet excitons to doped acceptors were observed. The probabilities of energy transfer were analyzed with a model that diffusing excitons transfer their energy to acceptors by dipole-dipole interactions. From the temperature dependence of the probabilities the diffusion coefficient D of an exciton was determined as 1/D=1/α'T^<-1/2>+1/βT^<1/2>{exp(hν/kT)-1}, where ν is the frequency of the longitudinal optical phonon. This result means that the transport effective mass of exciton is constant in the exciton band of a naphthalene crystal. Above 250 K, the temperature dependence of energy transfer was analyzed with a thermal activation process of the excited acceptor by an exciton.
社団法人日本物理学会の論文
1974-05-15