Emission Spectroscopy, Infrared
Published Online: 15 SEP 2006
Copyright © 2000 John Wiley & Sons, Ltd. All rights reserved.
Encyclopedia of Analytical Chemistry
How to Cite
Keresztury, G. 2006. Emission Spectroscopy, Infrared. Encyclopedia of Analytical Chemistry. .
- Published Online: 15 SEP 2006
Infrared emission spectroscopy (IRES) is a branch of experimental infrared (IR) spectroscopy that can be considered as an alternative to the more commonly used IR absorption or reflection techniques for observing vibrational transitions in molecular systems. While these methods provide spectral data that are similar regarding their information content (structural, analytical), IRES may have definite advantages (or drawbacks) depending on the object to be studied.
This article aims at giving an up-to-date account of the theory, instrumentation and laboratory practice of IRES. Following an introduction to the principles and nature of thermal radiation, the governing laws of IRES are outlined and analyzed in some depth, with the aim of defining the conditions for obtaining analytically meaningful IR emission spectra. Spectral distortions concomitant with the measurement of condensed-phase samples and other sources of error are pointed out along with the procedures devised for their elimination. Various methods of excitation of thermal radiation and the instrumentation most often used in laboratory measurements of IR emission spectra are described, with emphasis on modern Fourier transform (FT) techniques and with an outlook to special applications like remote sensing and process monitoring. Attention is given to data manipulation and presentation of emission spectra in relation to quantitative evaluation of spectral data. Recent advances in sample handling techniques, for example allowing the measurement of optically thick samples or thin surface layers, are also reviewed, while reference is given to the original sources of literature in the field.