Electron transfer attenuation coefficient

The rate constants for electron transfer and recombination are readily separated because in the limit (w- 0), equation (8.31) tends to kir/(ktr + krec), and the maximum of the semicircle occurs when ca = 2ir f=kt + krec. In the absence of RC attenuation effects, the high frequency intercept of the IMPS plot (minority carriers. Measurements of gac as a function of potential (band bending) can be used to determine the minority carrier lifetime and absorption coefficient [46]. The main advantage of using the IMPS data rather than dc measurements of... 

The dependence of the logarithm of the rate constants of electron transfer (log kEr) between the donor (D) and acceptor (A) centers on the D-A distances is similar to the correspondent dependence for the superexchange attenuation coefficient (log Yet) (Fig.2.6). Therefore, we can conclude that, similar to primary events in RCs from bacteria, the primary fast electron transfers take place as nonadiabatic and conformationally nonequilibrium processes. 

Gorman and coworkers have prepared five generations of dendrimers with cores composed of iron-sulfur clusters and with dendritic branches of varying flex-ibihty[44, 45]. Electrochemical measurements were carried out to determine diffusion coefficients as well as heterogeneous electron-transfer rates. The rate of electron transfer decreased monotonically with increasing dendrimer size, and the rigid dendrimers exhibited a much larger attenuation of the rate of electron transfer than the flexible ones [45]. 

---