Beratan, DN; Hopfield, JJ, *CALCULATION OF ELECTRON TUNNELING MATRIX ELEMENTS IN RIGID SYSTEMS: MIXED-VALENCE DITHIASPIROCYCLOBUTANE MOLECULES.*,
Journal of the American Chemical Society, vol. 106 no. 6
(1984),
pp. 1584-1594 [pdf] .
**Abstract:**

*A semiempirical model is presented which predicts photoassisted electron-transfer rate dependence on distance for redox groups connected by rigid polymeric linkers. The model approximately reproduces the observed decay of the optical tunneling matrix element with distance found for the rigid ruthenium dithiaspiro mixed-valence complexes of C. A. Stein, N. A. Lewis, G. J. Seitz, and H. Taube. The method calculates the through-bond propagation of the wave function tail, by a method which emphasizes obtaining the correct distance dependence of the tunneling matrix element for these weakly interacting donor-acceptor complexes. The method also allows prediction of the magnitude of the matrix element, the importance of hole or electron tunneling in the transport process, the effect of donor and acceptor redox potential on the matrix element, and the thermal tunneling matrix element for these and other compounds.*