Franck-Condon transfer

Figure 9. Illustration of how change in Fermi energy (Ep) acts on the energy barrier. E = potential energy C = Nuclear configuration p1 = density of filled metallic states in metal electrode. (A). Gurney s model8 with initial (I) and final (F) states at the same potential. (B). Non-Franck-Condon transfer in equilibrium. (C). Non-Franck-Condon transfer out of equilibrium.

Figure 1 Potential energy wells for the electron localized on the donor (D) and acceptor (A) sites. The parameter (A ) indicates the average energy gap for an instantaneous (Franck-Condon) transfer of the electron from the donor HOMO to the acceptor LUMO. The dotted lines show the electronic energies on the donor and acceptor at a nonequilibrium nuclear configuration with a nonequilibrium energy gap AE. The upper dashed horizontal line indicates the bottom of the conduction band of the electrons in the solvent.

Franck-Condon transfer of electron Relaxation of complex after transfer (4)... 

The Franck-Condon principle reflected in tire connection between optical and tliennal ET also relates to tire participation of high-frequency vibrational degrees of freedom. Charge transfer and resonance Raman intensity bandshape analysis has been used to detennine effective vibrational and solvation parameters [42,43]. 

Forster, Th 211, 278, 282, 285 Forster resonance energy transfer, 282 Forster singlet energy transfer, 378 Franck-Condon factors, 23 Franck-Condon principle, 5 Franck-Condon transition, 5 French, C. S., 555 Friedman, G., 353 Fritzsche, J., 37 Frosch, R. P 252, 267, 269 Fumaronitrile, photodimerization in solid state, 478... 

Note that the lability principle is formulated first of all for transferable electrons and atoms. An increase in their lability leads as a rule to an increase in the overlapping of the wave functions. For atoms the latter means a decrease in the Franck-Condon barrier. 

Developed into a power series in R 1, where R is the intermolecular separation, H exhibits the dipole-dipole, dipole-quadrupole terms in increasing order. When nonvanishing, the dipole-dipole term is the most important, leading to the Forster process. When the dipole transition is forbidden, higher-order transitions come into play (Dexter, 1953). For the Forster process, H is well known, but 0. and 0, are still not known accurately enough to make an a priori calculation with Eq. (4.2). Instead, Forster (1947) makes a simplification based on the relative slowness of the transfer process. Under this condition, energy is transferred between molecules that are thermally equilibriated. The transfer rate then contains the same combination of Franck-Condon factors and vibrational distribution as are involved in the vibrionic transitions for the emission of the donor and the adsorptions of the acceptor. Forster (1947) thus obtains... 

Evaluation of the Work Term from Charge Transfer Spectral Data. The intermolecular interaction leading to the precursor complex in Scheme IV is reminiscent of the electron donor-acceptor or EDA complexes formed between electron donors and acceptors (21). The latter is characterized by the presence of a new absorption band in the electronic spectrum. According to the Mulliken charge transfer (CT) theory for weak EDA complexes, the absorption maximum hv rp corresponds to the vertical (Franck-Condon) transition from the neutral ground state to the polar excited state (22). 

The simplest electron transfer reactions are outer sphere. The Franck-Condon principle states that during an electronic transition, electronic motion is so rapid that the metal nuclei, the metal ligands, and solvent molecules do not have time to move. In a self-exchange example,... 

The Franck-Condon principle states that there must be no movement of nuclei during an electronic transition therefore, the geometry of the species before and after electron transfer must be unchanged. Consequently, the active site geometry of a redox metalloenzyme must approach that of the appropriate transition state for the electronic transfer. Every known copper enzyme has multiple possible copper oxidation states at its active site, and these are necessary for the enzyme s function. 

Figure 6.22 Rearrangement of polar solvent dipoles (arrows) during the electron transfer process R + M — R + M. The initial stage is a vertical (Franck-Condon) electron transfer, and this is followed by reorganisation of the solvent dipoles...

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