Exact formula of the bridge-mediated donor-acceptor effective couplingD. J. Bicout1, 2, F. Varchon1 and E. Kats1, 3
1 Institut Laue-Langevin - 6 rue Jules Horowitz, B.P. 156, 38042 Grenoble, France
2 Biomathematics and Epidemiology, ENVL-TIMC B.P. 83, 69280 Marcy l'Etoile, France
3 L. D. Landau Institute for Theoretical Physics, RAS - 117940 GSP-1, Moscow, Russia
received 20 January 2005; accepted in final form 24 March 2005
published online 13 April 2005
An exact expression of the bridge-mediated donor-acceptor effective coupling, Hda, is derived. For systems represented by a tight-binding Hamiltonian with nearest-neighbor interactions, we show that |Hda|2 is equal to the product over all squares of nearest-neighbor couplings divided by an appropriate product of level spacing of eigen energies of the Hamiltonian. These results are subsequently compared with those obtained using perturbation approaches.
34.70.+e - Charge transfer.
73.40.Gk - Tunneling.
82.30.Fi - Ion-molecule, ion-ion, and charge-transfer reactions.
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