Evidence for diffusion-controlled electron transfer in exciplex formation reactions.Medium reorganisation stimulated by strong electronic coupling

摘要

Diffusion-controlled rates of formation were found from the temperature dependence of apparent quenching rate constants for exciplexes,when the driving force of excited-state electron transfer-0.1 < DELTAG_(ET)~* <+0.1 eV.This is inconsistent with the conventional mechanism of electron-transfer reactions,involving preliminary reorganisation of the medium and reactants,and provides strong support for the mechanism of medium reorganisation stimulated by strong electronic coupling of locally excited and charge-transfer states.