Electron transfer process free energy curves

The potential energy surfaces on which the electron-transfer process occurs can be represented by simple two-dimensional intersecting parabolic curves (Figure 6.23). These quantitatively relate the rate of electron transfer to the reorganisation energy (A.) and the free-energy changes for the electron-transfer process (AG°) and activation (AG ). 

Following the early studies on the pure interface, chemical and electrochemical processes at the interface between two immiscible liquids have been studied using the molecular dynamics method. The most important processes for electrochemical research involve charge transfer reactions. Molecular dynamics computer simulations have been used to study the rate and the mechanism of ion transfer across the water/1,2-dichloroethane interface and of ion transfer across a simple model of a liquid/liquid interface, where a direct comparison of the rate with the prediction of simple diffusion models has been made. ° ° Charge transfer of several types has also been studied, including the calculations of free energy curves for electron transfer reactions at a model liquid/liquid... 

Figure 17.5 Free energy curves and kinetic parameters for an electron transfer process.

Figure 17.6 Free energy curves for reactant and product states of an electron transfer process in the kinetic regimes of the Marcus model.

Figure 2.10 Parabolic free energy curves for heterogeneous electron transfer processes... 

The free energy curves allow one to discuss the energetics involved in the two types of charge transfer processes. For thermal electron transfer reactions, the... 

Electrocatalysis, Fundamentals - Electron Transfer Process Current-Potential Relationship Volcano Plots, Fig. 1 Effect of electrode potential on the free energy versus coordinate curves for an electron reactant at two electrode potentials E = Ee and E < Ee (broken line parabola)... 

The characteristic emission has a distinct energy threshold (appearance potential), which occurs at E = Ep (i.e., for 1 = 2 = 0). This results in the transfer of both the incident and core electrons to Ep, as shown in Figure 2. This event is signaled by the appearance of a small bump in the total emission versus incident electron energy curve. The excitation process is the same for all APS spectra. It seems that differences in the decay step are responsible for the spectral differences between SXAPS, AEAPS, and DAPS. In terms of this model DAPS provides information directly about the excitation process and is free of the relaxation complications. SXAPS and AEAPS include additional information dependent on the different decay (relaxation) steps. 

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