EFFECT OF VARIATION OF DIELECTRIC-CONSTANT ON THE MAGNETIC-FIELD MODULATION OF EXCIPLEX LUMINESCENCE

The effect of variation of dielectric constant on the relative magnetic field effect in singlet luminescence has been studied using a typical exciplex system at a saturating field. The study indicates strong specificity in the perturbation of the magnetic field effect by alcoholic solvents. In contrast to alcohols where relative singlet magnetic field effect is of the order of 2% only, the magnetic field effect in non-alcoholic medium reaches as high as 9%. Moreover, dielectric constant variation in alcohols yields curves which are distinctly different from those in non-alcoholic media. It turns out that this dependence of magnetic field effect on dielectric constant is similar in all non-alcoholic solvent mixtures. An analytical study based on Hong and Noolandi's solution of Smoluchowski equation has been made. Derived expressions can interpret experimental curves reasonably well. © 1990 Indian Academy of Sciences.