Franck-Condon solvent situation

Figure 3.41 Free energy surfaces S0 and 5, for a frozen solvent situation with the solvent equilibrated to the S0 charge distribution at the Franck-Condon geometry, indicating the lack of a Cl This should be contrasted with Figure 3.40 for the isolated chromophore.

A point that deserves attention is the contribution of the electronic solvent polarization to the solvatochromic shifts. Most force fields use atomic point charges that include the effect of electron polarization in an implicit way. The main problem with the use of this implicit description of the electronic polarization is that it gives a vanishing contribution when one compares situations where the solvent structure is fixed, for instance when the Franck-Condon principle is applied in vertical transitions. In these situations it is convenient to have a model to compute explicitly... 

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