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 energ y 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 reorganiza tion energies are determined by simulating the absorption and RR spect ra. The results indicate that the vibrational reorganization energy fo r 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 ha s greater contribution than its reorientational counterpart in acetoni trile, as expected, whereas the reverse trend is observed in benzonitr ile. (C) 1998 Published by Elsevier Science B.V. All rights reserved.