Study on the Turning Effect of the Energy Gap of π Electron on Atomic Vibration in Conjugated Linear Polymer
HE Xin2, 4, SUN Mei-jiao1, 2, LI Shuo2, GAO Shu-qin2, SUN Cheng-lin2, LI Zuo-wei1, 2, HE Zhi1, SONG Wen-zhi3*
1. State Key Laboratory of Superhard Materials, Jilin University, Changchun 130012, China 2. College of Physics, Jilin University, Changchun 130012, China 3. China-Japan Union Hospital，Jilin University，Changchun 130031，China 4. Material Science and Technology College, Jilin University, Changchun 130012, China
Abstract：The Visible absorption and Raman spectra of β-carotene were measured in dimethyl sulfoxide in temperature ranging from 81 to 25 ℃ and in carbon disulfide in pressure range from 0.04 to 0.60 GPa, respectively. The results indicated that the visible absorption and Raman spectra are both red-shifted, Raman scattering cross section increase with the temperature decreasing. And with the pressure increasing, the visible absorption spectra are red-shifted, but the frequency shift towards higher frequencies in the Raman spectra, the Raman scattering cross section decrease unexpectedly. The latter can’t be explained by the model of “effective conjugation length” and “coherent weakly damped electron-lattice vibrations”. In this paper, we combined electron-vibration coupling rule with theoretical calculations and found that the electron-phonon coupling constant had a certain changing trend with the temperature and pressure variation, which Indicate that the interaction between π-electron and CC bond vibration was essential for this experiment result. Thus, the turning effect of energy gap of the π on CC vibration mode is responsible for such phenomenon.
Key words：Polymer molecule;Electron-phonon coupling;Energy gap
贺 欣2, 4，孙美娇1,2，李 硕2，高淑琴2，孙成林2，里佐威1, 2，何 志1，宋文植3* . 线性多烯分子的π电子能隙对原子振动的调制 [J]. 光谱学与光谱分析, 2016, 36(11): 3455-3460.
HE Xin2, 4, SUN Mei-jiao1, 2, LI Shuo2, GAO Shu-qin2, SUN Cheng-lin2, LI Zuo-wei1, 2, HE Zhi1, SONG Wen-zhi3* . Study on the Turning Effect of the Energy Gap of π Electron on Atomic Vibration in Conjugated Linear Polymer . SPECTROSCOPY AND SPECTRAL ANALYSIS, 2016, 36(11): 3455-3460.
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