Triplet-Energy and Electron Transfer Rates

The expectation arises that accurate Franck-Condon factors could be calculated by a model incorporating a suitable high frequency and a good estimate of the reorganisation energy. In terms of the relations presented above 

The comparison between the bond-length changes of the systems indicated in Table 15.2 requires some reference state. Considering that these systems follow Pauling s relation, the reference state can be found multiplying l/ox 4edl respective bond orders, or, better, the average of the bond order because the effective displacement is independent of the choice of the initial and final states. This takes into account the fact that smaller bond 

Bond lengths and displacements (in angstrom) of diatomic molecules and ions with bond-order differences of 0.5 

The heuristic validation of eq. (15.135) for the calcrrlation of effective displacements for triplet-energy and electron transfers tmder the specified conditions has interesting consequences. The isomorphism of eqs. (15.135) and (7.9), suggests that the energy dependence of the effective displacement should have the form of eq. (7.8), or, more precisely. 

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