Exciton Diffusion in Naphthalene Crystals

Exciton capture by anthracene in naphthalene crystals is studied as a function of impurity concentration (4×${10}^{-8\mathrm{}}$ to 4.8×${10}^{-3\mathrm{}}$), temperature, annealing, and wavelength of exciting radiation. It is shown that surface, incoherent, and possibly coherent free excitons participate in these excitonic processes. A method for annealing molecular crystals is described. Some observations on the temperature dependence of these processes are reported.