The Electronic states of mixed molecular crystals. II. Application of the mixed crystals of naphthalene and deuteronaphthalenes

Calculations have been made of the exciton band structure of the naphthalene crystal in a periodic volume of 10 x 10 x 10 unit cells. Levels belonging to special values of wave vector are reported for the crystal structure at room temperature and at 95 °K. It is found that the ac polarized spectrally active level lies at the bottom of the exciton band, in agreement with experiment. The pure crystal levels are used in a calculation of the properties of dilute mixed crystals of naphthalene-h8 in various deuterated naphthalene host crystals. Then the variation of optical properties with concentration is treated, the guests being assumed to form superlattices within the host structure. The dilute crystal results, and those for variation with concentration, agree satisfactorily with experiment.