RESONANCE RAMAN INTENSITY ANALYSIS OF NONLINEAR OPTICAL CHROMOPHORES IN LIQUID AND POLYMER SOLUTIONS

Abstract: This paper reports resonance Raman scattering for nonlinear optical chromophores in liquid organic solvents and in polymer matrices. Resonance Raman Intensity Analysis is performed to determine the mode-specific reorganization energies for the chromophores and solvent broadening parameters. Resonance Raman Intensity Analysis is a powerful technique for determining detailed information regarding the nuclear motions that are coupled to electronic excitation immediately following photoexcitation.1 By measuring the absolute resonance Raman intensity, reorganization energies are obtained for both the internal modes of the chromophore and the surrounding solvent modes that are coupled to the electronic transition. The lowest energy electronic transition of donor-π-acceptor nonlinear optical chromophores, such as Disperse Red, is an intense charge-transfer transition. Using a simple two level model, the nonlinear optical properties of the Disperse Red chromophore are determined, in part, by the ground state dipole moment and the transition dipole moment for this lowest energy charge-transfer transition.2 The large dipole change for this transition is accompanied by significant solvent reorganization and thus it is of interest to determine the magnitude of the solvent reorganization fo