Dexter electron transfer
Encyclopedia
Dexter electron transfer is a quenching mechanism
in which an excited electron state transfers from one molecule (the donor) to a second (the acceptor). This requires a wavefunction overlap between the donor and acceptor, so can only occur at short distances; typically of the order 15-20Å. The excited state may be exchanged in a single step, or in two separate charge exchange steps.
The Dexter energy transfer rate,
, is proportional to the expression:
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:
Quenching (fluorescence)
Quenching refers to any process which decreases the fluorescence intensity of a given substance. A variety of processes can result in quenching, such as excited state reactions, energy transfer, complex-formation and collisional quenching. As a consequence, quenching is often heavily dependent on...
in which an excited electron state transfers from one molecule (the donor) to a second (the acceptor). This requires a wavefunction overlap between the donor and acceptor, so can only occur at short distances; typically of the order 15-20Å. The excited state may be exchanged in a single step, or in two separate charge exchange steps.
The Dexter energy transfer rate,
, is proportional to the expression: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: