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Infrared Fourier Transform Emission Spectroscopy

机译:红外傅里叶变换发射光谱

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摘要

Traditionally high-resolution infrared spectra of gas-phase molecules are recorded in absorption and the advantages of acquiring infrared emission spectra have largely been overlooked. As this article will illustrate, using mainly our own work, all else being equal, infrared emission spectroscopy is more sensitive than absorption spectroscopy. Since transient molecules have low concentrations because of their great chemical reactivity, it is advantageous to use emission spectroscopy to study them. The infrared region of the electromagnetic spectrum provides a unique window for monitoring molecular processes. Mainly vibra-tional transitions of molecules are found in the infrared, although there are infrared electronic transitions and infrared pure rotation transitions. In general, vibrational transitions carry specific chemical group information in a way that electronic and pure rotational transitions do not. It is for a good reason that the organic chemist refers to the 900 - 1400 cm~(-1) interval as the 'fingerprint region'. All molecules, except homonuclear diatomics, have at least one electric-dipole-allowed vibrational transition. Even homonuclear molecules such as H_2 have weak electric-quadrupole transitions which are used by astronomers to detect molecular clouds that are experiencing shock waves. Vibrational transitions are thus a universal, molecule-specific monitor of chemical composition; every major industrial laboratory and university chemistry department has at least one infrared spectrometer.
机译:传统上,气相分子的高分辨率红外光谱记录在吸收中,获取红外发射光谱的优势已被大大忽略。正如本文将说明的那样,在其他所有条件相同的情况下,主要是使用我们自己的工作,红外发射光谱比吸收光谱更敏感。由于瞬态分子由于其强大的化学反应性而具有较低的浓度,因此使用发射光谱研究它们是有利的。电磁光谱的红外区域为监视分子过程提供了一个独特的窗口。尽管存在红外电子跃迁和红外纯旋转跃迁,但主要在红外中发现了分子的振动跃迁。通常,振动跃迁以电子和纯旋转跃迁没有的方式携带特定的化学基团信息。有机化学家将900-1400 cm〜(-1)间隔称为“指纹区域”是有充分理由的。除同核双原子外,所有分子均具有至少一个允许电偶极子振动的跃迁。甚至H_2之类的同核分子也具有弱的四极电跃迁,天文学家使用它们来检测正在经受冲击波的分子云。因此,振动跃迁是一种通用的,特定于分子的化学成分监测器。每个主要的工业实验室和大学化学部门都有至少一个红外光谱仪。

著录项

  • 来源
    《Chemical Society Reviews》 |1996年第2期|p.111-115|共5页
  • 作者

    Peter F. Bernath;

  • 作者单位
  • 收录信息 美国《科学引文索引》(SCI);美国《生物学医学文摘》(MEDLINE);美国《化学文摘》(CA);
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 化学;
  • 关键词

  • 入库时间 2022-08-18 00:41:06

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