Marcus electron transfer

R. A. Marcus, Electron-transfer reactions in chemistry - theory and experiment (Nobel Lecture), Angew. Chem. Int. Ed. 1993, 32, 1111. 

Thus, the model incorporating the direct hole trapping by adsorbed dichloroacetate molecules, which has been proposed by Bahnemann and co-workers, appears to be probable [7]. Moreover, calculations using the Marcus electron transfer theory for adiabatic processes which result in a reorientation energy of 0.64 eV suggest that also in the case of SCN- the hole transfer occurs in the adsorbed state [7]. 

The factors governing electron transfer may be described within the framework of the Marcus electron-transfer theory (175). They are expressed in terms of driving force, distance of redox centers, reorganization energy, etc. 

Figure 2. Marcus electron transfer plot for the process DBA D" BA [7], The electronic coupling between the two states is defined as the energy difference A at the avoided crossing. A decreases exponentially with bridge length.

Decosta, D. P., Pincock, J. A., Photochemistry of Substituted 1 Naphthylmethyl Esters of Phenylacetic and 3 Phenylpropanoic Acid Radical Pairs, Ion Pairs, and Marcus Electron transfer, J. Am. Chem. Soc. 1993, 115, 2180 2190. 

On the other hand, it is striking to note that transition state theory has been applied extensively in quantum chemistry ever since the computational facilities needed for this were made available, while Marcus Electron Transfer (ET) theory has only been used systematically since the last decade. 

Interpretation of the kinetic pulse radiolysis data for intramolecular Trp — Tyr radical transformation in aqueous solutions of linear H-Trp-(Fro)rr-Tyr-OH, n = 0-5, is presented in terms of the Marcus electron transfer theory, taking into account conformational dynamics of the molecules. For this purpose, for each peptide, representative sets of low-energy conformers were selected with the help of experimental methods ( H and NMR, and circular dichroism) and modeling meth-... 

In Marcus electron transfer theory, the barrier also arises as a consequence of the intersection of the two diabatic potential energy curves. The barrier height depends mainly on the (solvent and reactant) reorganization energy. 

Fig. 8.2 Oxidation potential of model electrolyte clusters vs. the rate estimated from the Marcus electron transfer theory. EC(—H) denotes a neutnil EC radical with one proton abstracted from it in the process of the oxidation-induced reaction. Oxidation potentials are from M05-2X/6-31+G calculations with PCM(e=20) [16]. Rates were ceilculated in this work...

It is possible to describe the antiferromagnetic term in Equation (5) in the same conceptual basis as that for Marcus electron-transfer theory " and the Hush model for intervalence transitions.Bertrand considered the case of electron transfer between biological molecules coupled by an exchange interaction. This is represented schematically by two metal sites separated by a bridging medium L (Scheme 1). 

For route 2, charge transport mechanism is similar to the hopping mechanism of small molecules. According to the charge transport theory developed hy Bredas et al. [22], the charge carrier transport in organic materials can be described by Marcus electron transfer theory (Eq. 1.3). In organic ciystals, the AG is 0 because the electron transfer happens in a same kind of molecules. Thus the Eq. 1.3 formula can be simplified into Eq. 1.4 as follows ... 

A unified view has been published of the Marcus electron transfer and Mullikan charge transfer theories as applied in organometallic chemistry.In... 

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