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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C_5H_5N在CH_3OH和H_2O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.C_7H_8和m-C_8H_(105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△随压强改变而引起W改变;b.随压强增加CCl_4在C_6H_6中的v_1+v_4~v_3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CO_2的费米共振影响较大,而对CS_2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。 相似文献
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在二硫化碳(CS2)和苯(C6H6)的二元溶液中,随着相对体积浓度而变化,C6H6的基频ν1(992 cm-1) 的拉曼散射系数随浓度减小而增加,而CS2的基频ν1(656 cm-1)的拉曼散射系数则随浓度增加而增加。文章测量了这二元溶液相对不同体积浓度的拉曼光谱。结果表明,尽管CS2和C6H6的基频ν1的强度都随着浓度变化而发生较大变化,但C6H6的基频ν1对其参与的ν1+ν6~ν8费米共振几乎没有影响,而CS2的基频ν1强度的变化不仅对ν1~2ν2费米共振产生较大影响,还使基频ν2发生变化。文章给出了实验结果,并用Bertran费米共振理论和群论给予了解释。 相似文献
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The Fermi resonance behaviours of the two groups of binary solutions --- pyridine and methanol, benzene and carbon tetrachloride, under different pressures are investigated according to their Raman spectra. The effect of pressure on Fermi resonance in binary solution differs significantly from that in pure liquid. In a binary solution, with the intermolecular distance shortening, the intermolecular interaction potential increases, the shift rates of the Raman spectral lines increase, the spectral line splitting occurs ahead of that in pure liquid, and the wavenumber separation Δ0 between the unperturbed harmonic levels shifts more quickly, too. The Fermi resonance parameters, the coupling coefficient W and the intensity ratio R of the two Raman bands, decrease rapidly with pressure increasing, and the pressure at which Fermi resonance phenomenon disappears is much lower than that in pure liquid, especially in the solution whose molecules are of the same polarity. This article is valuable in the identification and the assignment of spectral lines under high pressure, as well as the study of high pressure effect, intermolecular interaction, and solvent effects in different cases, etc. 相似文献
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