Transient Effect in Fluorescence Quenching by Electron Transfer. 3. Distribution of Electron Transfer Distance in Liquid and Solid Solutions

We have calculated the distribution Y(r) of electron transfer distance which is defined in such a way that Y(r) d r represents the probability of electron transfer over a distance between r and r + d r . The effect of Δ G on the Y(r) distribution was evaluated using the following parameters: the transfer integral J 0 at 6 Å, its attenuation coefficient β with distance, and the diffusion coefficient D . These parameters have already been determined experimentally ( J 0 and β) or empirically ( D ) in a previous paper ( J. Phys. Chem. 1995, 99, 5354). The parameter values were then changed to include the more commonly used solvent, acetonitrile, and a wide range of electron transfer rates. These results indicate that the distribution is not only a function of Δ G but also a function of the quencher concentration. These results cannot be obtained simply by referring to the distance dependence of the rate constant of the reaction. The distribution considered here has experimental significance, since it is directly related to the yield of free ions.