Effect on Fermi Resonance by Some External Fields: Investigation of Fermi Resonance According to Raman Spectra
JIANG Xiu-lan1, SUN Cheng-lin2, ZHOU Mi2, LI Dong-fei3, MEN Zhi-wei2, LI Zuo-wei2*, GAO Shu-qin2
1. School of Science, Qingdao Technological University, Qingdao 266033, China 2. College of Physics, Jilin University, Changchun 130021, China 3. Changchun Observatory, National Astronomical Observatories, Chinese Academy of Sciences, Changchun 130117, China
摘要： 费米共振是分子内和分子间发生的基团间的振动耦合和能量转移现象。有关外场中费米共振的认识、拉曼光谱的研究方法及应用均待开发和推广。本文系统阐述了利用高压DAC技术、变温技术特别是课题组独创的变换溶剂浓度、LCOF等方法获得的有关费米共振的研究成果，即分子场、压力场、温度场等外场对分子内和分子间费米共振的影响：(1)分子场中 a. 由C5H5N在CH3OH和H2O中拉曼光谱变化研究表明溶剂效应对费米共振有明显影响; b. 通过改变溶液浓度发现了其他方法未能发现的费米共振双线对非对称移动及双线对中倍频的基频亦受费米共振调谐的现象; c. 溶液中的氢键、反氢键使分子基团重组而对费米共振产生显著影响; d. C7H8和m-C8H10分子间发生会费米共振，且费米共振特性随溶液浓度明显改变;(2)压力场中 a. 随压强增加谱线蓝移，且频差Δ随压强改变而引起W改变;b. 随压强增加CCl4在C6H6中的ν1+ν4～ν3的W减小速度比纯液体中快，费米共振消失提前。这表明，压强引起的费米共振现象可揭示溶剂效应机理;(3)温度场中 温度会影响分子费米共振特性，且对不同分子影响亦不同，温度对CO2的费米共振影响较大，而对CS2几乎无影响。本文对分子谱线的认证与归属、分子构象的确定及异构体的鉴别、氢键对分子结构与性质的影响等方面的研究提供了系统的理论与实验依据。
关键词：外场;费米共振;拉曼光谱
Abstract：Fermi resonance is a phenomenon of molecular vibrational coupling and energy transfer occurred between different groups of a single molecule or neighboring molecules. Many properties of Fermi resonance under different external fields, the investigation method of Raman spectroscopy as well as the application of Fermi resonance, etc need to be developed and extended further. In this article the research results and development about Fermi resonance obtained by Raman spectral technique were introduced systematically according to our work and the results by other researchers. Especially, the results of the behaviors of intramolecularand intermolecular Fermi resonance of some molecules under some external fieldssuch as molecular field, pressure field and temperature field, etc were investigated and demonstrated in detail according to the Raman spectra obtained by highpressure DAC technique, temperature variation technique as well as the methods we planed originally in our group such as solution concentration variation method and LCOF resonance Raman spectroscopic technique, and some novel properties ofFermi resonance were found firstly. Concretely, (1) Under molecular field. a. The Raman spectra of C5H5N in CH3OH and H2O indicates that solvent effect can influence Fermi resonance distinctly; b. The phenomena of the asymmetric movement of the Fermi resonance doublets as well as the fundamental involved is tuned by the Fermi resonance which had not been found by other methods were found firstly by our variation solution concentration method; c. The Fermi resonance properties can be influenced distinctly by the molecular group reorganization induced by the hydrogen bond and anti-hydrogen bond in solution; d. Fermi resonance can occurred between C7H8 and m-C8H10, and the Fermi resonance properties behave quite differently with the solution concentration;(2) Under pressure field. a. The spectral lines shift towards high wavenumber with increasing pressure, and frequency difference Δ varies with pressure, whichinduced the change of W; b. The W of ν1+ν4～ν3 of CCl4 in C6H6 decreased more quickly in solution than in pure liquid with increasing pressure and the Fermi resonance disappeared ahead of that in pure liquid, which indicates that the phenomenon of Fermi resonance induced by pressure effect can reveal the mechanism of some solvent effects. (3) Under temperature field. a. The Fermi resonance properties of different molecules behave quite differently with temperature. For an instance, the one of CO2 can be influenced distinctly by temperature, while the one of CS2 behaves no change with temperature. This article offers systematic theoretical and experimental support to the investigation of identification and assignment of molecular spectral line, the confirmation of molecular conformation and conformers, the effect of hydrogen bond on molecular structure and properties, etc.
蒋秀兰1，孙成林2，周 密2，李东飞3，门志伟2，里佐威2*，高淑琴2 . 几种外场对费米共振的影响：费米共振的拉曼光谱研究 [J]. 光谱学与光谱分析, 2015, 35(03): 635-639.
JIANG Xiu-lan1, SUN Cheng-lin2, ZHOU Mi2, LI Dong-fei3, MEN Zhi-wei2, LI Zuo-wei2*, GAO Shu-qin2 . Effect on Fermi Resonance by Some External Fields: Investigation of Fermi Resonance According to Raman Spectra. SPECTROSCOPY AND SPECTRAL ANALYSIS, 2015, 35(03): 635-639.
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