Magnetic-field effect on the diphenyl hexatriene-dimethyl aniline exciplex system: anisotropic effects in viscous media

Abstract

The exciplex formed between diphenyl hexatriene and dimethyl aniline has been found to be magnetic-field sensitive. The effect of the dielectric constant of the medium and of addition of an alcohol on the magnetic-field modulated luminescence of the exciplex has been discussed. Theoretical B ½ values have been calculated by the INDO-UHF method. The lack of correspondence between the theoretical and the experimental B ½ values has been explained on the basis of electron hopping. In a viscous polymeric medium, anisotropic interactions between the radical partners have been observed. A qualitative explanation of this novel phenomenon, emphasizing the importance of anisotropic dipolar interactions, has been discussed. To the best of our knowledge, this is the first report on magnetic anisotropy of exciplex luminescence.