Temperature effect on the resonance Raman spectra of all-trans-β-carotene in iodine solution

The resonance Raman spectra of the fundamental, combination, and second harmonic modes around the carbon-carbon single and double bonds stretches of all-trans-β-carotene in 1, 2-dichloroethane with iodine solution are obtained in the range of 293-83 K. The Raman scattering cross section of the fundamentals in the liquid (293-213 K) and solid phases (188-83 K) increases as temperature decreases and the Raman bandwidths decreases. An intriguing phenomenon is that the Raman scattering cross section of the carbon-carbon single and double bonds in solution with iodine decreases and the Raman bandwidths increases, compared with the one without iodine. These phenomena are analyzed using the coherent weakly damped electron - lattice vibration mode.