Charge transfer, process-oriented

This chapter reviews electron transfer models, develops molecular models of the solvent surrounding ions of different types to provide a more complete picture of the orientational changes taking place, especially in cases where electron transfer is combined with atom transfer, where assembly of a solvation sphere is required during the process. Finally, the activation energies of some charge-transfer processes are given. 

Hengerer R., Kavan L., Krtil P. and Gratzel M. (2000), Orientation dependence of charge-transfer processes on Ti02 (anatase) single crystals , J. Electrochem. Soc. 147, 1467-1472. 

It was mentioned that manipulation of energy profile diagrams (Fig. 2) gives a simple significance to p. However, this is a grossly oversimplified representation since the course of activation in a charge transfer process involves intermolecular and orientational... 

To summarize, in situ IR spectroscopy allows the adsorption of organic molecules at semiconductor electrodes to be studied with a sensitivity on the order of 0.1 ML and provides information not only on the chemical identity of the surface species and their orientation but also on the nature of the charge transfer processes at the interface and the surface hydrophobicity/hydrophilicity. Because of the instability of adsorbed xanthate, the surface composition of the electrode after decoupling from the electrochemical system differs from that existing under an applied potential. 

It should be noted that the dynamics studied by fluorescence methods is the dynamics of relaxation and fluctuations of the electric field. Dipole-orientational processes may be directly related to biological functions of proteins, in particular, charge transfer in biocatalysis and ionic transport. One may postulate that, irrespective of the origin of the charge balance disturbance, the protein molecule responds to these changes in the same way, in accordance with its dynamic properties. If the dynamics of dipolar and charged groups in proteins does play an important role in protein functions, then fluorescence spectroscopy will afford ample opportunities for its direct study. 

---