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The resonance Raman spectra of nonpolar molecule all-trans--carotene and polar molecule canthaxanthin in nonpolar CS2 and polar 1,2-dicholoroethane in a temperature range from 243K to 293K are measured. The results show that polarities of the solute and solvent have a great effect on Raman spectrum. Raman scattering cross-section of nonpolar all-trans--carotene in nonpolar solvent CS2 is biggest and its bandwidth is narrowest. Raman scattering cross-section of polar canthaxanthin in polar solvent 1,2-dicholoroethane is smallest and its bandwidth is widest. The experimental phenomena are explained by solvent effects, coherent weakly damped electron-lattice vibration and effective conjugated length.







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