Rotation-vibration interactions in the spectra of polycyclic aromatic hydrocarbons: Quinoline as a test-case species.
Rotation-vibration interactions in the spectra of polycyclic aromatic hydrocarbons: Quinoline as a test-case species.
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多环芳烃光谱中的旋转振动相互作用：喹啉作为测试案例物种。
DOI：
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发表时间：
2015
影响因子：
4.4
通讯作者：
G. Mouret
中科院分区：
文献类型：
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作者：
O. Pirali;Z. Kisiel;M. Goubet;S. Gruet;M. Martin‐Drumel;Arnaud Cuisset;F. Hindle;G. Mouret
多环芳烃（PAHs）与天体物理学高度相关，因为在许多不同的天体中观察到的未识别红外发射带的载体可能存在争议。为了支持射电天文观测，高分辨率实验室光谱学已经提供了几种这种类型分子振动基态的转动光谱，尽管最近才有可能使用有限数量的实验装置来研究它们密集的红外（IR）波段。迄今为止，所有的旋转分辨数据都涉及未扰动光谱。我们目前报告的结果的三个最低振动态的喹啉C9 H7 N，含氮萘衍生物的高分辨率研究。当喹啉的纯转动基态光谱未受微扰时，ν45和ν44振动模的光谱出现严重的复杂化（分别位于168 cm（-1）和178 cm（-1）处）。为了详细研究这些影响，我们采用了三种不同的和互补的实验技术：傅里叶变换微波光谱，毫米波光谱，傅里叶变换远红外光谱与同步辐射源。由于在分子的红外光谱的高密度的状态作为大的多环芳烃，扰动的旋转光谱的激发态应该是无处不在的。我们的研究首次确定了这种影响，并提供了一些见解，以适当的治疗这种扰动。
Polycyclic aromatic hydrocarbons (PAHs) are highly relevant for astrophysics as possible, though controversial, carriers of the unidentified infrared emission bands that are observed in a number of different astronomical objects. In support of radio-astronomical observations, high resolution laboratory spectroscopy has already provided the rotational spectra in the vibrational ground state of several molecules of this type, although the rotational study of their dense infrared (IR) bands has only recently become possible using a limited number of experimental set-ups. To date, all of the rotationally resolved data have concerned unperturbed spectra. We presently report the results of a high resolution study of the three lowest vibrational states of quinoline C9H7N, an N-bearing naphthalene derivative. While the pure rotational ground state spectrum of quinoline is unperturbed, severe complications appear in the spectra of the ν45 and ν44 vibrational modes (located at about 168 cm(-1) and 178 cm(-1), respectively). In order to study these effects in detail, we employed three different and complementary experimental techniques: Fourier-transform microwave spectroscopy, millimeter-wave spectroscopy, and Fourier-transform far-infrared spectroscopy with a synchrotron radiation source. Due to the high density of states in the IR spectra of molecules as large as PAHs, perturbations in the rotational spectra of excited states should be ubiquitous. Our study identifies for the first time this effect and provides some insights into an appropriate treatment of such perturbations.