FLUORESCENCE LIFETIMES OF SUBSTITUTED INDOLES IN SOLUTION AND IN FREE JETS - EVIDENCE FOR INTRAMOLECULAR CHARGE-TRANSFER QUENCHING

Fluorescence lifetime measurements for a variety of substituted indoles were taken in cyclohexane and in supersonic gas expansions. When the two data sets were compared, a strong trend became evident. Solvent polarizability effects can be seen as stabilizing intramolecular charge-transfer quenching processes in the substituted indoles that are stimulated by the correct placement of charge accepting/releasing substituents.