Electron transfer in condensed media: Failure of the Born-Oppenheimer and Franck-Condon approximations, collective phenomena and detailed balance relationship

Abstract

A new theoretical approach for elementary electron transfer in condensed media has been established, in which a failure of the Born-Oppenheimer and Franck-Condon approximations, and collective phenomena of the large number of tunnel and over-barrier transitions are of paramount importance. Experimental results obtained recently on temperature T dependences of rate constant and activation energy have corroborated this approach for electron transfer in Langmuir-Blodgett film devices. Where tunnel luminescence and absorption of the light through the mechanism of elementary electron transfer are involved, a strong linear displacement of their bands into the blue region as T increases has been predicted; the Stokes shift is temperature-independent. The bands grow exponentially in intensity as T increases. The relationship between the luminescence and absorption bands has been obtained. The theory has been established both in the case of the equivalent interactions of the electron with phonons of the medium for the electron localized at a donor or at an acceptor and where these interactions are different. In the former case, the theory employs ordinary quantum mechanics, whereas in the latter case, the theory additionally employs an original postulate entered into quantum mechanics by the author. This postulate makes it possible to redress the detailed balance relationship between forward and reverse process of electron transfer, which fails due to the asymmetry resulting from the different interactions at a donor and at an acceptor.