title: Phase-transition induced changes in the electron-phonon coupling of all-trans-β-carotene.
abstract: The resonance Raman spectra of the fundamental, combination, and second harmonic modes around the C-C and C=C stretches of all-trans-β-carotene in 1,2-dichloroethane solution are obtained in the 323-83 K temperature range. The Raman scattering cross-section of the fundamentals in the liquid and solid phases generally increases as the temperature decreases, except for the liquid-solid phase transition, which exhibits a decreasing trend. The relative Raman intensities of the combination and harmonic modes of the CC bonds increase as the temperature decreases. The Raman bandwidths of the C=C bonds gradually become narrow but then appear a turning-point in the phase transition. The temperature-induced fundamental modes are analyzed using a coherent weakly damped electron-lattice vibration model and resonant Raman effects. The changes in the combination and harmonic modes are interpreted using the aforementioned model as well as the theory of electron-phonon interaction.
authors.affiliation: College of Physics, Jilin University, Changchun 130012, PR China.
authors.forename: Guannan
authors.initials: G
authors.lastname: Qu
authors.forename: Meijiao
authors.initials: M
authors.lastname: Sun
authors.forename: Shuo
authors.initials: S
authors.lastname: Li
authors.forename: Chenglin
authors.initials: C
authors.lastname: Sun
authors.forename: Tianyuan
authors.initials: T
authors.lastname: Liu
authors.forename: Shengnan
authors.initials: S
authors.lastname: Xu
authors.forename: Zhiwei
authors.initials: Z
authors.lastname: Men
authors.forename: Zuowei
authors.initials: Z
authors.lastname: Li
mesh_terms: D004583:Electrons; D005025:Ethylene Dichlorides / Q000737:chemistry; D044367:Phase Transition; D060739:Phonons; D013059:Spectrum Analysis, Raman; D019207:beta Carotene / Q000737:chemistry*
chemical_list: D005025:Ethylene Dichlorides; D019207:beta Carotene; C024565:ethylene dichloride