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Coupling decay factor, electron transfer

The electronic coupling of the reactant state with the product state, F, is a function of the overlap of the donor and acceptor orbitals. This in turn depends on energetic, spatial, geometric, and symmetry factors. At relatively large donor acceptor separations, it can be assumed that the relevant orbitals decay exponentially with distance. In these cases, the electron transfer rate constant will depend on this separation as per Eq. 2, where Rda is the donor-acceptor separation and y is a constant that expresses the sensitivity of the... [Pg.1937]

The distance decay constant / (see below) in Miller et al. s original study was 0.9 per CH2, using ferricyanide and iron(IH) hexahydrate [44]. In a later study which accounted more thoroughly for double layer effects, 2 was determined to be 1 eV for kinetically facile redox probes such as ferricyanide, 1.3 eV for Ru-hexamine and 2.1 eV for iron(III) hexahydrate. With a better understanding of the redox probe behavior, f was found to be 1.08 + 0.20 per CH2 and independent of the redox couple and electrode potential [96]. Pre-exponential factors were also extracted from the Tafel plots. The edge-to-edge rate constants (extrapolated) are approximately 10 -10 s for all redox probes, which is reasonable for outer-sphere electron transfer. The pre-exponential factors are 5 x lO s [96]. [Pg.2932]

The shorter decay (instrument-limited) was attributed to the fluorescence from adsorbred molecules strongly coupled to the surface, indicating that the electron transfer rate is much faster than 40 ps. In order to get a more accurate value for the injection rate, the integrated fluorescence intensities of the fast component of the sensitized semiconductor decay curve were compared with the intensity of the oxazine on the tape reference sample [48]. This analysis yielded a quenching factor of about 10 . From this an electron injection rate of 3 x lO s corresponding to an electron transfer time of around 40 fs, was obtained. [Pg.322]


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See also in sourсe #XX -- [ Pg.5 ]




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Electron coupling

Electron electronic factor

Electron transfer coupling

Electron transfer electronic coupling

Electron transfer factors

Electronic coupling

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