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) dr represents the probabilit y of electron transfer over a distance between r and r + dr. The effec t of Delta G on the Y(r) distribution was evaluated using the followin g parameters: the transfer integral J(0) at 6 Angstrom, its attenuatio n coefficient beta with distance, and the diffusion coefficient D. The se parameters have already been determined experimentally (J(0) and be ta) or empirically (D) in a previous paper (J. Phys. Chem. 1995, 99, 5 354). The parameter values were then changed to include the more commo nly used solvent, acetonitrile, and a wide range of electron transfer rates. These results indicate that the distribution is not only a func tion of Delta G but also a function of the quencher concentration. The se results cannot be obtained simply by referring to the distance depe ndence of the rate constant of the reaction. The distribution consider ed here has experimental significance, since it is directly related to the yield of free ions.