Infrared spectroscopy of CH stretching vibrations of jet-cooled alkylbenzene cations by using the "messenger" technique
Infrared spectroscopy of CH stretching vibrations of jet-cooled alkylbenzene cations by using the "messenger" technique
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使用“信使”技术对喷射冷却烷基苯阳离子的 CH 伸缩振动进行红外光谱分析
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发表时间：
2000
期刊：
影响因子：
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通讯作者：
N. Mikami
中科院分区：
文献类型：
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作者：
A. Fujii;E. Fujimaki;T. Ebata;N. Mikami
利用红外-紫外双共振和红外光解光谱分别观察了喷流膨胀法制备的苯- ar、甲苯- ar和乙苯- ar团簇在中性基态和阳离子基态下的CH伸缩振动。这些团簇的平面内模的振动频率已被发现与相应的裸分子的振动频率几乎相同。芳香族CH的拉伸振动在电离后表现出高频位移，其红外吸收强度显著降低。在电离作用下，烷基CH伸展振动的频率和强度也发生了显著变化。密度泛函计算较好地再现了观测到的中性态和阳离子态红外光谱，并指出了阳离子态超共轭的增强。
The CH stretching vibrations of the benzene–Ar, toluene–Ar, and ethylbenzene–Ar clusters prepared in jet expansion were observed in both the neutral and cationic ground states by using infrared–ultraviolet double resonance and infrared photodissociation spectroscopy, respectively. Vibrational frequencies for the in-plane modes of the clusters have been found to be practically the same as those of the corresponding bare molecules. The aromatic CH stretching vibrations showed high frequency shifts upon ionization, and their infrared absorption intensities remarkably decreased. The alkyl CH stretching vibrations were also significantly changed in both frequency and intensity upon ionization. Density functional calculations well reproduced the observed infrared spectra of the neutral and cationic states, and enhancement of hyperconjugation in the cationic state was pointed out.