【摘要】 本文利用红外一真空紫外光谱实验方法和量子化学理论计算方法研究了中性三甲胺双聚体的红外光谱和结构.2975和2949 cm^-1这两个峰属于C-H非对称伸缩振动,2823 cm^-1峰属于C-H对称伸缩振动.2739 cm^-1峰属于CH₃弯曲振动的泛频峰,它在红外激光能量小于1 mJ/mm²时不会被观测到.2773 cm^-1峰可能属于费米共振.实验和理论的研究结果表明,中性三甲胺双聚体存在多种同分异构体.中性三甲胺二聚体红外光谱的半峰宽没有受到结构变换的显著影响,使得伸缩振动模式得到很好的分辨.更多还原

【Abstract】 Infrared-vacuum ultraviolet（IR-VUV） spectra of neutral trimethylamine dimer were measured in the 2500-3800 cm^-1 region. Quantum chemical calculations were performed to identify the structure of the low-lying isomers and to assign the observed spectral features.The bands at 2975 and 2949 cm^-1 were assigned to the antisymmetric C-H stretching and the band at 2823 cm^-1 to the symmetric C-H stretching, respectively. The 2739 cm^-1band was due to the CH3 bending overtone, which disappeared at low IR laser power of1 mJ/mm². The extra band at 2773 cm^-1 could be due to Fermi resonance behavior of the light isotopologue, these are often close in energy and can strongly mix through cubic terms in the potential function. Experimental and theoretical results indicate the likely coexistence of multiple structures. The peak widths of IR spectra of neutral trimethylamine dimer are not significantly affected by the structural transformation, allowing the stretching modes to be well resolved.更多还原