Contribution of Dipolar Coupling to the Mechanism of the Triplet-Triplet Energy Transfer Process at Long Distances: A Doluble Resonance and Laser Line Narrowing Study

摘要

The results of the temporal behavior of the phosphorescence emission are analyzed when excited at different laser frequencies within the inhomogeneous linewidth of the 0,0 band of the singlet triplet absorption of an orientationally disordered solid (1-bromo-4-chloronaphthalene) at 4.2 K. This enabled the examination of the triplet triplet energy transfer probability as a function of the donor acceptor distance by simply changing the laser frequency. The deviation from the expected temporal behavior for the electron times or large donor acceptor distances is discussed in terms of either a contribution of dipolar coupling to the transfer mechanism or a change in the dimensionality of the system undergoing the transfer process. Results of the phosphorescence microwave double resonance techniques could lend support to the possibility of a contribution of the dipolar coupling to the triplet triplet transfer at large donor acceptor distances (i.e., long wavelength laser excitation). Keywords: Energy Transfer; Double Resonance; Laser Line Narrowing; Disordered Solids; Dimensionality.