Reorganization effects

Another approach is to measure the redox potential at different temperatures and to calculate AH° and AS0. However, these thermodynamic terms also depends on both protein intrinsic factors and solvent reorganization effects. In general, the... 

If we accept this as an estimate of the inner-sphere contribution to the term AGFC(I2-) in Scheme 2, it suggests that not more than half of the observed Franck- Condon barrier can be attributed to solvent reorganization effects. 

J. N. Chazalviel and A. V. Rao, Optical absorption by surface states and atomic reorganization effects at the semiconductor/electrolyte interface, J. Electrochem. Soc. 134, 1138, 1987. 

The electrostatic term GENP is accompanied by a second term GCDS which, as the acronym indicates, collects cavitation, dispersion, and solvent structure contributions, the latter regarding dielectric saturation and other reorganization effects, when present. GCDS is modeled in terms of an interfacial atomic surface tension term, <7fc, and of the parameter Ak giving the solvent-accessible surface area for atom k ... 

Any in-depth analysis of chemical shifts really should take into account a full quantum-chemical description of the emitting atom in the excited state of a partly covalent bonding situation. Then not only are the excited electronic states of the bare atom relevant for the photoemission spectrum, but also the reorganization effects of the hybridized electronic states of the ligand atoms around the photoemitter. The analysis of shake-up satellites, which arise from interactions of the ejected photoelectron with the hgand molecular orbitals, is a prominent... 

Using this approach, values of P = 0.6-1.2 A have been reported for covalently bound donor-acceptor systems [20,28-31]. However, many of the reported data have not been properly corrected for reorganization effects and may thus represent only an upper limit to the distance dependence of / da- A recent comparison of activationless ET rate constants obtained from several different covalent donor-acceptor compounds yields a value of P = 0.7 A [13]. 

ET rate constants in these systems decreased from a value of k i = 3.6 X 10 s for 36 to ka 50 s" for 39. Analysis of the activation parameters for these reactions demonstrated that solvent reorganization effects have a signiflcant effect in governing the distance dependence of intramolecular ET rates and that the electronic factor in these systems follows an attenuation factor of P = 0.68 A" using the through-space distance estimate of 3.12 A per residue. Unfortunately, accurate values for AH and A5 could not be obtain for the n = 4 compound (39), which was not included in the analysis. Interestingly, Schanze and Cabana [49] observed a nearly identical distance dependence of the activation parameters for ka occurring between a rhenium bipyiidyl electron acceptor and a (di-methylamino)benzoate donor across zero to two proline residues. 

Inner-sphere reorganization effects are clearly seen in reactions of the complexes [Co(A4)(OH2)2]" (A4 = planar macrocyclic tetramine). Only the Co-0 bond lengths change appreciably from the 3 + to the 2 -I- ion, and rates of self-exchange correlate with this change. ... 

The reorganization effects relate the thermodynamic free energy difference AG between reactants and products to the transition state activation free energy AG that actually determines the rate constant in (111). Combining (112)-(114) we obtain the form of the rate constant for electron transfer ... 

The symmetry breakdown of AFne, given in Table 8, shows that AVmio) is greatly reduced from that in DME and AFne( r) becomes <0, i.e., antibarrier. Consequently a bonding and cr reorganization effects appear to represent the key barrier energy determinant in methanol. 

Ganguli (1217) investigated the spin equilibrium by H NMR spectroscopy in different solvents observations being interpreted in terms of preferential solvation or second coordination sphere reorganization effects. This work also suggests that neglect of pseudo-contact shift can lead to erroneous conclusions about spin delocalization mechanisms, which occur in these systems by direct ji delocalization along the alkyl chain. 

The charge terms expressed in Cartesian coordinate space are very difBcult to inter] et. Besides, as we shall later see, its elements will carry some contributions frmn the compensatory rotation of polar molecules stipulated by the Edcart-Sayvetz conditions. In the Decius proach, on the other hand, the consideration of diese rotational effects is explicit and, as result, both the effective chaiges and charge fluxes determined are purely intramolecular quantities reflecting the charge reorganization effects acconqiaiiying vibrational distortions. 

---