Partitioning of the total reorganization energy into its vibrational and solvent (inertial and reorientational) contributions using resonance Raman intensities

The concept and determination of inertial solvent reorganization energy for an intramolecular charge-transfer process are presented in this Letter. Resonance Raman (RR) spectra have been recorded for 4-nitro,4′-dimethylamino-azobenzene (DA) within the charge-transfer transition, in acetonitrile and benzonitrile. Mode-specific and solvent reorganization energies are determined by simulating the absorption and RR spectra. The results indicate that the vibrational reorganization energy for DA is comparable in the two solvents and the difference is observed mainly in the solvent reorganization energy that has been partitioned into inertial and reorientational components. The inertial response has greater contribution than its reorientational counterpart in acetonitrile, as expected, whereas the reverse trend is observed in benzonitrile.