MAGNETIC-FIELD EFFECTS ON EXCIPLEX LUMINESCENCE IN WATER-TETRAHYDROFURAN AND WATER-DIOXANE MIXTURES

Magnetic-field-modulated exciplex luminescence in different solvent me dia has been studied to verify the solvent microheterogeneity effect. In particular, mixtures of a low-polarity component, such as dioxane a nd tetrahydrofuran, and a highly polar component, such as water, have been used as media where the microheterogeneity has been further modul ated by addition of salt and variation of temperature. The results are analysed in light of several proposed models for the solvent effect o n MFE's, but no model is found to be completely satisfactory. It has b een suggested that multiple intermediate states, instead of a single i ntermediate state, are formed during the electron-transfer process.