Triboluminescence of 3,6-dibromocarbazole

3,6-Dibromocarbazole was identified to be triboluminescent for the first ti me. From the triboluminescence and photoluminescence spectra, it was found that the room-temperature triboluminescence spectrum of 3,6-dibromocarbazol e, unlike most other triboluminescent materials, was different from its pho toluminescence spectrum at the same temperature and was composed of a weak tribofluorescence and a strong tribophosphorescence. This result can be asc ribed partly to the "heavy atom effect" caused by the two bromine substitue nts and partly to the change in luminescence quantum yields experienced dur ing the breakage of the crystals, Its symmetry of crystalline structure was determined to belong to the acentric space group using the method of secon d-harmonic generation.