Development of Autoionization-Detected Infrared Spectroscopy for Molecular Cations

分子阳离子自电离检测红外光谱的发展

• 批准号: 09640591
• 负责人: FUJII Asuka
• 金额: $ 1.66万
• 依托单位: Tohoku University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1997
• 资助国家: 日本
• 起止时间: 1997 至 1998
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09640591/
• 关键词: INFRARED SPECTROSCOPY; HYDROGEN BOND; RYDBERG STATE; AUTOIONIZATION; ION; DOUBLE RESONANCE; FLUOROPHENOL; CRESOL; リュードベリ状態; 超音速分子線; フェノール

A new technique for infrared spectroscopy of isolated bare molecular ions in a supersonic jet was developed. High Rydberg states, of which ion core has the same structure as the corresponding bare ion, were state-selectively pumped by two-color double resonance excitation. Infrared absorption of the ion core was measured by detecting molecular ions produced by vibrational autoionization. By using this technique, which is called "autoionization-detected infrared (ADIR) spectroscopy", the following results have been obtained ;(a) The OH stretching vibrations of fluorophenol and methoxyphenol cations were observed, providing the first direct evidence for intramolecular hydrogen bonds in molecular cations.(b) The OH stretching vibration of the cresol cation was observed, and it was found that the OH frequency showed clear dependence on the orientation to the neighboring methyl group. This result indicates the presence of a new type of intramolecular hydrogen bonding between the hydroxyl and methyl groups.(c) The first observation of CH stretching vibrations in aromatic cations were performed. The aromatic and alkyl CH stretches in the ethyiphenol cation were observed, and the aromatic CH showed high-frequency shifts upon the ionization.

发展了一种超声射流中孤立裸分子离子红外光谱的新技术。采用双色双共振激发，对高里德堡态进行了态选择性泵浦，高里德堡态的离子核与相应的裸离子具有相同的结构。通过检测振动自电离产生的分子离子来测量离子核的红外吸收。通过使用这种技术，这是所谓的“自动电离检测红外光谱（ANOMS）”，已获得以下结果：（a）氟苯酚和甲氧基苯酚阳离子的OH伸缩振动观察，提供了第一个直接证据分子内氢键的分子阳离子。(b)观察到甲酚阳离子的OH伸缩振动，发现OH频率与相邻甲基的取向有明显的依赖关系。这一结果表明羟基和甲基之间存在一种新型的分子内氢键。(c)首次观察到芳香族阳离子的CH伸缩振动。在乙基苯酚阳离子中观察到芳香族和烷基CH伸缩，并且芳香族CH在电离时显示高频位移。

项目成果

Takayuki Ebata, Asuka Fujii, and Naohiko Mikami: "Vibrational spectroscopy of small-sized hydrogen-bonded clusters and their ions." Int.Rev.Phys.Chem.17. 331-361 (1998)

Takayuki Ebata、Asuka Fujii 和 Naohiko Mikami：“小型氢键簇及其离子的振动光谱。”

Asuka Fujii: "Autoionization-detected infrared spectroscopy of molecular ions" The Journal of Physical Chemistry A. 101・34. 5963-5965 (1997)

藤井飞鸟：“分子离子的自电离检测红外光谱”《物理化学杂志》A. 101・34（1997）。

Asuka Fujii: "A New Type of Intramolecular Hydrugen Bonding : Hydroxyl-Methyl Interactions in the o-cresol cation" Journal of the American Chemical Society. 120・50. 13256-13257 (1998)

Asuka Fujii：“新型分子内氢键：邻甲酚阳离子中的羟基-甲基相互作用”美国化学会杂志 120・50（1998）。

Asuka Fujii: "Observation of intramolecular hydrogen bonds of o-fluorophenol ions by using autoionization detected infrared spectroscopy" Chemistry Letters. 1099-1100 (1997)

Asuka Fujii：“使用自电离检测红外光谱观察邻氟苯酚离子的分子内氢键”化学快报。

Asuka Fujii: "A new type of intramolecular hydrogen bonding : Hydroxyl-methyl interactions in the o-cresol cation" Journal of American Chemical Society. 120・50. 13256-13257 (1998)

Asuka Fujii：“新型分子内氢键：邻甲酚阳离子中的羟甲基相互作用”美国化学会杂志 120・50（1998）。