Dexter electron transfer


Dexter electron transfer is a fluorescence quenching mechanism in which an excited electron is transferred from one molecule to a second molecule via a non radiative path. This process requires a wavefunction overlap between the donor and acceptor, which means it can only occur at short distances; typically within 10 Å. The excited state may be exchanged in a single step, or in two separate charge exchange steps.

History

This short range energy transfer process was first theoretically proposed by D. L. Dexter in 1953.

Rate expression

The Dexter energy transfer rate,, is indicated by the proportionality
where is the separation of the donor from the acceptor, is the sum of the Van der Waals radii of the donor and the acceptor, and is the spectral overlap integral defined by