Charge transfer General Subject

The Lorenz concept of partial charge transfer was subject to general criticism by Parsons, Damaskin, and other authors and these critical views are well summarized in the lUPAC recommendations [1] in connection with these matters ... 

If these conditions are not satisfied, some process will be involved to prevent accumulation of the intermediates at the interface. Two possibilities are at hand, viz. transport by diffusion into the solution or adsorption at the electrode surface. In the literature, one can find general theories for such mechanisms and theories focussed to a specific electrode reaction, e.g. the hydrogen evolution reaction [125], the reduction of oxygen [126] and the anodic dissolution of metals like iron and nickel [94]. In this work, we will confine ourselves to outline the principles of the subject, treating only the example of two consecutive charge transfer processes O + n e = Z and Z 4- n2e — R. 

This chapter concerns the energetics of charge-transfer (CT) reactions. We will not discuss subjects dealing with nuclear dynamical effects on CT kinetics. " The more specialized topic of employing the liquid-state theories to calculate the solvation component of the reorganization parameters is not considered here. We concentrate instead on the general procedure of the statistical mechanical analysis of the activation barrier to CT, as well as on its connection to optical spectroscopy. Since the very beginning of ET research, steady-state optical spectroscopy has been the major source of reliable information about the activation barrier and preexponential factor for the ET rate. The main focus in this chapter is therefore on the connection between the statistical analysis of the reaction activation barrier to the steady-state optical band shape. 

Since the discovery of the surface enhancement effect, it has been the subject of much debate as to what the origins of the effect are. It is generally understood that there are several mechanisms which are responsible for the observed enhancement. There are two main theories electromagnetic enhancement and charge-transfer or chemical enhancement which will be mentioned only briefly here. 

There have been two reviews of photoinduced electron transfer. The subject is dealt with generally in one " whilst ultrafast photochemical charge transfer and excited state solvation are considered specifically in the other. ... 

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