Electron transfer energy diagrams

Fig. 5. Potential energy-reaction coordinate diagram for an electron transfer reaction leading to a product adsorbed on the electrode surface.

Fig. 12. Energy-reaction coordinate diagram for electron transfer in solution when there is only weak interaction between the initial and final energy states.

FIGURE 34.3 Electron energy diagram. A fluctuation of the solvent polarization brings the energy levels and to the resonance position. After the electron transfer, the occupied energy level relaxes to its equilibrium position for the reduced form Ared-... 

As with the phase diagrams and Pourbaix diagrams, the theoretical standard hydrogen electrode also allows us to calculate the relative energies of intermediates in electrochemical reactions. As an example, we investigate the oxygen reduction reaction (ORR). We look at the four proton and electron transfer elementary steps ... 

Just as above, we can derive expressions for any fluorescence lifetime for any number of pathways. In this chapter we limit our discussion to cases where the excited molecules have relaxed to their lowest excited-state vibrational level by internal conversion (ic) before pursuing any other de-excitation pathway (see the Perrin-Jablonski diagram in Fig. 1.4). This means we do not consider coherent effects whereby the molecule decays, or transfers energy, from a higher excited state, or from a non-Boltzmann distribution of vibrational levels, before coming to steady-state equilibrium in its ground electronic state (see Section 1.2.2). Internal conversion only takes a few picoseconds, or less [82-84, 106]. In the case of incoherent decay, the method of excitation does not play a role in the decay by any of the pathways from the excited state the excitation scheme is only peculiar to the method we choose to measure the fluorescence (Sections 1.7-1.11). 

FIGURE 6.6 Potential energy diagram for the theory of electron transfer reactions. The activated complex is at S. For reasonably fast reactions, the reactant adheres to the lower curve and slithers into the product curve through the activated complex—that is, an adiabatic electron transfer occurs. 

Fig. 2 (a) Schematic representation of the energy levels diagrams for a DBA system and a MBM junction in which the electron transfer process is dominated (b) by superexchange or non-resonant tunnelling, (c) by resonant tunnelling or (d) by hopping ... 

Figure 1.13 Potential energy diagrams describing electron transfer processes according to Marcus theory. (A) Self-exchange (B) Cross Reaction.

Figure 1. Schematic representation of the artificial photosynthetic reaction center by a monolayer assembly by A-S-D triad and antenna molecules for light harvesting (H), lateral energy migration and energy transfer, and charge separation across the membrane via multistep electron transfer (a) Side view of mono-layer assembly, (b) top view of a triad surrounded by H molecules, and (c) energy diagram for photo-electric conversion in a monolayer assembly.

Fig. 2 Free energy diagram for electron transfer. Solid curve represents free energy of the equilibrium state, E = Eoq. Dashed curve represents free energy of for E = Eoq + r. ... 

Fig. 18 Potential energy diagram qualitatively illustrating the relationship between the charge-transfer excitation energy and the thermal barrier to electron transfer in...

Use simple molecular orbital diagrams to show the various processes of photoinduced energy transfer and photoinduced electron transfer. 

Figure 1. Potential energy vs. normal mode coordinate for symmetrical electron transfer, AE = 0. As shown, the diagram is in the classical (high temperature) limit where h

Figures 4-11 and 4-12 show schematic energy diagrams for the electron transfer from the standard gaseous state through the electrolyte solution into the metal electrode. As mentioned in Chap. 2, the electron level (the real potential of electron) a s/v> in an electrolyte solution consists of an electrostatic energy...

Fig. 4-11. Energy diagram for electron transfer from a standard gaseous electron across a solution/vacuum interface, through an electrolyte solution, and across a metal/solution interface into a metal electrode = real potential of electrons e,s) in electrolyte...

Figures 8-5 and 8-6 are energy diagrams, as functions of electron energy e imder anodic and cathodic polarization, respectively, for the electron state density Dyf.t) in the metal electrode the electron state density AtEDox(c) in the redox particles and the differential reaction current ((e). From these figures it is revealed that most of the reaction current of redox electron transfer occurs in a narrow range of energy centered at the Fermi level of metal electrode even in the state of polarization. Further, polarization of the electrode potential causes the ratio to change between the occupied electron state density Dazc/itnu md the imoccupied...

Fig. 8-23. Energy diagram for a redox electron transfer via the conduction band of semiconductor electrode (a) anodic redox electron transfer, (b) cathodic redox electron transfer.

Fig. 8-29. Energy diagram for the most probable electron level, eck, of oxidant particles and the conduction band edge level, Bq, in a cathodic redox electron transfer via the conduction band cathodic current is maximum when cqx equals e. ...

Fig. 10-26. Energy diagram for a cell of photoelectrolytic decomposition of water consisting of a platinum cathode and an n-type semiconductor anode of strontium titanate of which the Fermi level at the flat band potential is higher than the Fermi level of hydrogen redox reaction (snao > epM+zHj) ) he = electron energy level referred to the normal hydrogen electrode ri = anodic overvoltage (positive) of hole transfer across an n-type anode interface t = cathodic overvoltage (negative) of electron transfer across a metallic cathode interface.

Figure 9.8 Simple diagram of mitochondrial H -ion movement and axonal K -ion movement to establish membrane potentials across membranes. Note that H movement from the mitochondrial matrix to the outer surface of the inner membrane requires a specific proton pump that requires energy, which is transferred from electron transfer, whereas the K ion movement occurs via an ion channel with energy provided from the concentration difference of K ions on either side of the membrane (approximately 100-fold). The movement of both the protons and K ions generates a membrane potential. The potential across the membrane of the nerve axon provides the basis for nervous activity (see Chapter 14).

Scheme 3.1. Schematic energy level diagram comparing (a) the radical-anion substrate and (b) the radical-anion radical-anion coupling routes for the clcctrodimerization process. Wavy lines indicate an electron transfer step.

Figure 4.5, Potential energy diagrams for the homogeneous electron transfer reaction between an aromatic radical-anion and a second aromatic with a frangible R-X bond, (a) The situation where back electron transfer and bond cleavage have similar free energy of activation, (b) The situation where the RX radical-anicm has high energy and the R-X bond has low dissociation ertergy.

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