Mixed-valence vibronic coupling

Inclusion of Solvent Effects in a Vibronic Coupling Model for Mixed-Valence Compounds... 

A vibronic coupling model for mixed-valence systems has been developed over the last few years (1-5). The model, which is exactly soluble, has been used to calculate intervalence band contours (1, 3, 4, 5), electron transfer rates (4, 5, 6) and Raman spectra (5, 7, 8), and the relation of the model to earlier theoretical work has been discussed in detail (3-5). As formulated to date, the model is "one dimensional (or one-mode). That is, effectively only a single vibrational coordinate is used in discussing the complete ground vibronic manifold of the system. This is a severe limitation which, among other things, prevents an explicit treatment of solvent effects which are... 

Piepho has responded to the criticisms of the PKS model by developing an improved version, the MO vibronic coupling model for mixed-valence complexes (32). Multicenter vibrations are now considered and a molecular orbital basis set (as with the three-site model) is used. This model was used to calculate band shape and g values for the Cretuz-Taube ion (33). The MO vibronic coupling model is admittedly more empirical than the three-site model but it has the advantage in being applicable to all mixed-valence complexes. 

Fig. 11.15. Temperature variation of the effective magnetic moment for the mixed-valence dl-dl-

The book Electrons in Chemical Reactions by L. Salem places electron transfer in a broad context ranging from basic wave mechanics to ion-solvent interactions. Sutin has reviewed theories of electron transfer with emphasis on nuclear, electronic, and frequency factors and Wong and Schatz have given a useful unified account of the dynamics of mixed-valence complexes using the vibronic coupling model. ... 

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