title: Effect of end groups on the raman spectra of lycopene and β-carotene under high pressure.
abstract: The Raman spectra of all-trans-lycopene in n-hexane were measured under high pressure, and the results compared with those of β-carotene. The different pressure effects on Raman spectra are analyzed taking into account the different structures of lycopene and β-carotene molecules. It is concluded that: (a) the vibronic coupling between the S₁ and S₀ states of β-carotene is stronger than that of lycopene, (b) the diabatic frequency increment of the ν₁ mode is more susceptible to pressure than that of the ν₂ mode for lycopene, and (c) β-rings rotation can relieve the pressure effect on the C=C bond length in β-carotene. This work provides some insights for elucidating the structural and environmental effects on Raman spectra of carotenoids.
authors.affiliation: Center for Condensed Matter Science and Technology, Department of Physics, Harbin Institute of Technology, Harbin 150001, China.
authors.forename: Ming-Ming
authors.initials: MM
authors.lastname: Huo
authors.forename: Wei-Long
authors.initials: WL
authors.lastname: Liu
authors.forename: Zhi-Ren
authors.initials: ZR
authors.lastname: Zheng
authors.forename: Wei
authors.initials: W
authors.lastname: Zhang
authors.forename: Ai-Hua
authors.initials: AH
authors.lastname: Li
authors.forename: Da-Peng
authors.initials: DP
authors.lastname: Xu
mesh_terms: D002338:Carotenoids / Q000737:chemistry*; D000077276:Lycopene; D011312:Pressure; D013059:Spectrum Analysis, Raman / Q000379:methods*; D019207:beta Carotene / Q000737:chemistry*
chemical_list: D019207:beta Carotene; D002338:Carotenoids; D000077276:Lycopene