Spectroscopy and Spectral Analysis, Volume. 34, Issue 5, 1302(2014)
Effect of Pressure on Electron-Phonon Coupling Constants of All-Trans-β-Carotene
The present paper cited that R.Tubino and other people introduced a kind of electron-phonon coupling constants with dimension, which can establish the relation with the Huang-Rhys factor and calculate the electron-phonon coupling constants of every C—C bond vibration mode. There are many reports about the visible absorption and Raman spectra of all-trans-β-carotene with pressure. But the study about the Raman scattering cross section and the Huang-Rhys factor with pressure have not been reported now. Visible absorption and Raman spectra of all-trans-β-carotene were measured in carbon disulfide in the pressure range from 0.04 to 0.60 GPa. The results indicated that the visible absorption spectra of β-carotene in nonpolar solvent carbon disulfide are red-shifted with pressure increasing, but the frequency shifts towards higher frequencies in the Raman spectra, the Raman scattering cross section decreases, Huang-Rhys factor increases, and the electron-phonon coupling constants of CC bond vibration modes increase. The mechanism is that all-trans-β-carotene caused by compression and a decrease in the structurally ordered properties of the molecules leads to narrow energy gap of the π, shortens effective conjugation length, hinders delocalization of π-electron, decreases the Raman scattering cross section, and increases the Huang-Rhys factor and the electron-phonon coupling constants.
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SUN Mei-jiao, WANG Kai, XU Sheng-nan, QU Guan-nan, LI Shuo, SUN Cheng-lin, ZHOU Mi, LI Zuo-wei. Effect of Pressure on Electron-Phonon Coupling Constants of All-Trans-β-Carotene[J]. Spectroscopy and Spectral Analysis, 2014, 34(5): 1302
Received: May. 13, 2013
Accepted: --
Published Online: May. 6, 2014
The Author Email: Mei-jiao SUN (mjsun12@mails.jlu.edu.cn)