Solvent Dynamic Effects on ET Reactions at Electrodes

SOLVENT DYNAMIC EFFECTS ON ET REACTIONS AT ELECTRODES 

However, a very limited number of studies focused on the effect of solvent dynamics on electron transfer reactions at electrodes.Smith and Hynes introduced the effect of electronic friction (arising from the interaction between the excited electron hole pairs in the metal electrode) and solvent friction (arising from the solvent dynamic [relaxation] effect) in the electron transfer rate at metallic electrodes. The consideration of electron-hole pair excitation in the metal without illumination by light seems unrealistic. 

The role of solvent dynamics in the electron transfer reaction at a Pt electrode was discussed utilizing the theory of Zusman. In this work, ° the solvent-dependent rate constant for the electron transfer reaction at an electrode was given as 

The solvent-dependent frequency factor is generally expressed as 

An inverse correlation occurs between the experimental value i.expi and the theoretical values of the standard rate constant k,caic when the latter is computed from Eq. (1) using the adiabatic value of the transmission coefficient(i.e.,/c= 1), the solvent-independent frequency factorv = A 77/i (see solid circles in Fig. 18), and the solvent dependence is taken into account only via continuum A., (het) values obtained from Eq. (3). 

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VIII. SOLVENT DYNAMIC EFFECTS ON ET REACTIONS AT ELECTRODES... 

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