Time-dependent Stokes shift and its calculation from solvent dielectric dispersion data

The time-dependent solvation correlation function (the Stokes shift response function), which describes the solvent response to a sudden change in the charge distribution of a solute molecule, is calculated here directly from experimentally measured dielectric dispersion data, epsilon(omega), of the solvent. In the calculation a reaction field with the dielectric continuum assumption is used. This simple model is applied to the experimental results of Jimenez et al. for photoexcited coumarin and water as a solvent, and encouraging agreement is obtained using the experimental data on epsilon(omega).