Raman spectroscopy study on the Fermi resonance of liquid carbon disulfide in binary solutions: Effect of the weak hydrogen bond formation on the Fermi resonance

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• 作者：DongFei Li ; Shang Sun ; ChengLin Sun ; XiuLan Jiang ; ShuQin Gao ; ZuoWei Li
• 关键词：Fermi resonance (FR) ; Raman spectroscopy ; Carbon disulfide
• 刊名：Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy
• 出版年：2012
• 出版时间：October, 2012
• 年：2012
• 卷：96
• 期：Complete
• 页码：193-199
• 全文大小：805 K

文摘

We have measured the Raman spectra of liquid CS₂ at different volume concentrations in CHCl₃ and CH₂Cl₂ solutions. With decreasing the volume concentration of CS₂, a noticeable growth in the band frequency was observed, while the band location remained practically unchanged. This asymmetric wavenumber shift phenomenon of the Fermi doublet and of CS₂ has been ascribed to weak, non-conventional hydrogen bonds formed between the CS₂ and the solvent molecules. These weak hydrogen bonds were also responsible for significant decreases in the C-H bond symmetric stretching vibration band frequencies of CHCl₃ and CH₂Cl₂. The values of the FR parameters of CS₂ in CH₂Cl₂ and CHCl₃ at different volume concentrations were calculated according to the FR theory. The magnitude of the FR coupling coefficient W of CS₂ increases upon dilution with CH₂Cl₂ and CHCl₃, indicating that the vibrational anharmonicity is relatively sensitive to variations in the weak hydrogen bonding. Compared with the changing tendencies of Fermi coupling coefficient W of CS₂ in CH₂Cl₂ and CHCl₃ at different volume concentrations, we discussed the effect of the weak hydrogen bond formation on the FR and the asymmetric wavenumber shift phenomenon of the Fermi doublet and of CS₂.