Accession Number : ADA213450


Title :   Dynamics of Electron Transfer for a Nonsuperexchange Coherent Mechanism. I


Descriptive Note : Technical rept. 1 Aug 1988-13 Oct 1989


Corporate Author : CALIFORNIA INST OF TECH PASADENA ARTHUR AMOS NOYES LAB OF CHEMICAL PHYSICS


Personal Author(s) : Marcus, R A ; Almeida, R


Full Text : http://www.dtic.mil/dtic/tr/fulltext/u2/a213450.pdf


Report Date : 13 Oct 1989


Pagination or Media Count : 27


Abstract : In addition to mechanisms such as superexchange and a chemical intermediate mechanism for electron transfer from a donor D* to an acceptor A via a molecular bridge B, and third possibility occurs when the BA electronic coupling is very strong and the D*B and D(+)B(-) states have energies moderately close to each other. This mechanism is discussed here. Like superexchange, it is a coherent one, in contrast to the chemical intermediate mechanism, where the transfer is sequential and incoherent. The dynamics of the mechanism are discussed, particularly the maximum population of 'B-' and the question of whether an effective rate constant. There are, as yet, no experimental data on the mechanism, though the synthesis of suitable D8BA's may permit is observation. In the treatment three collective nuclear coordinates are introduced, permitting independent reorganization energies for each reactive center. With certain approximations, namely, equal vibration frequencies and a nonadiabatic first step, the problem is reduced analytically to a one-coordinate one, which can be readily treated numerically. One rough but simple analytical result for the latter is also given. (AW)


Descriptors :   *CHEMICAL REACTIONS , *ELECTRON TRANSFER , ELECTRONICS , VIBRATION , EXPERIMENTAL DATA , REACTION KINETICS , SYNTHESIS , CHEMICALS , DYNAMICS , MOLECULES , COHERENCE , RATES , REACTIVITIES , BRIDGES , ADDITION , COUPLING(INTERACTION) , FREQUENCY


Subject Categories : Physical Chemistry


Distribution Statement : APPROVED FOR PUBLIC RELEASE