J. Jortner et M. Bixon, ELECTRON-TRANSFER AND INTRAMOLECULAR RADIATIONLESS TRANSITIONS, Journal of photochemistry and photobiology. A, Chemistry, 82(1-3), 1994, pp. 5-10
We outline the conceptual framework for the description of long-range
photoinduced electron transfer in isolated solvent-free supermolecules
and explore the dependence of the intramolecular electron transfer ra
tes from photoselected states on the molecular parameters, i.e. energy
gaps and mode-specific intramolecular reorganization energies. An ene
rgy gap law for the microscopic electron transfer rate was derived whi
ch, for relaxation from the electronic origins, exhibits a poissonian
energy gap dependence, with an exponential energy gap law for large ga
ps. The exponential energy gap law manifests the dominant role of nucl
ear tunnelling in the weak electron-nuclear coupling limit, being quan
titatively distinct from the thermal gaussian energy gap dependence.