dc.creator Harris, Charles B. en_US dc.date.accessioned 2006-06-15T13:29:58Z dc.date.available 2006-06-15T13:29:58Z dc.date.issued 1972 en_US dc.identifier 1972-D-1 en_US dc.identifier.uri http://hdl.handle.net/1811/8943 dc.description Author Institution: Department of Chemistry, University of California en_US dc.description.abstract Phosphorescence microwave double resonance experiments, in which changes in the intensity and /or polarization of phosphorescence from triplet excition states is monitored while a microwave field pumps the zero-field spin sublevels, are presented which experimentally differentiate between diffusion limited exciton migration and migration describable by the group velocity of the wave packet of k states, i.e., coherent exciton migration. The relationships between microwave spectroscopy, coherent triplet exciton migration and density of states functions in molecular crystals will be developed and illustrated for 1,2,4,5-tetra-chlorobenzene crystals which can be considered a model for a one-dimensional exciton. In addition, an electron spin resonance theory which incorporates explicitly exciton-phonon scattering into the Block equations and allows one to extract the temperature dependence of the coherence length will be presented and applied to 1,2,4,5-tetrachlorobenzene crystals which can be considered a model for a one-dimensional exciton. In addition, an electron spin resonance theory which incorporates explicitly exciton-phonon scattering into the Block equations and allows one to extract the temperature dependence of the coherence length will be presented and applied to 1,2,4,5-tetrachlorobenzene crystals. A coherence length of 10,000-30,000 {\AA} is experimentally found at $3.2^{\circ} K$ . Finally, arguments will be presented that suggest that below certain temperatures coherent exciton migration might be the rule rather than the exception in molecular crystals. en_US dc.format.extent 161867 bytes dc.format.mimetype image/jpeg dc.language.iso English en_US dc.publisher Ohio State University en_US dc.title COHERENT MIGRATION OF TRIPLET EXCITONS IN MOLECULAR CRYSTALS en_US dc.type article en_US
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