Abstract
Expressions are derived for the influence of host crystal and defect reabsorption, exciton trapping and thermal detrapping, and defect and impurity fluorescence on the fluorescence properties of a “pure” organic molecular crystal. The reabsorption spectra of crystal anthracene and its defects are discussed, and data on the thickness and temperature dependence of its fluorescence lifetime are analysed. The exciton transfer rate in “pure” anthracene crystals is time-independent at t > 0.1 ns.