Fourier transform infrared spectroscopy principle

Fourier Transform Infrared Spectroscopy Principles and Applications... 

Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy. Attenuated total redectance (atr) ftir spectroscopy is based on the principle of total internal redection (40). Methods based on internal redection in the uv and visible regions of the spectmm are also common in addition to those in the ir region. The implementation of internal redection in the ir region of the spectmm provides a means of obtaining ir spectra of surfaces or interfaces, thus providing moleculady-specific vibrational information. 

Spectroscopy has become a powerful tool for the determination of polymer structures. The major part of the book is devoted to techniques that are the most frequently used for analysis of rubbery materials, i.e., various methods of nuclear magnetic resonance (NMR) and optical spectroscopy. One chapter is devoted to (multi) hyphenated thermograviometric analysis (TGA) techniques, i.e., TGA combined with Fourier transform infrared spectroscopy (FT-IR), mass spectroscopy, gas chromatography, differential scanning calorimetry and differential thermal analysis. There are already many excellent textbooks on the basic principles of these methods. Therefore, the main objective of the present book is to discuss a wide range of applications of the spectroscopic techniques for the analysis of rubbery materials. The contents of this book are of interest to chemists, physicists, material scientists and technologists who seek a better understanding of rubbery materials. 

Between the source and the detector is put either monochromators used in dispersive instruments or interferometers used in Fourier transform infrared (FT-IR) instruments. In a dispersive instrument the intensity at each wavenumber is measured one by one in sequence and only a small spectral range falls on the detector at any one time. In a FT-IR instrument the intensities of all the wavenumbers are measured simultaneously by the detector. Fourier transform infrared spectroscopy offers some advantages compared to dispersive instruments, namely (i) higher signal-to-noise ratios for spectra obtained under conditions of equal measurement time, and (ii) higher accuracy in frequency for spectra recorded over a wide range of frequencies. Therefore we will give below a brief picture of the principle of FT-IR spectroscopy, based on a Michelson interferometer (Fig. 2). 

M. (2007) Variable-temperature rheo-optical Fourier-transform infrared spectroscopy of polymers, in Vibrational Spectroscopy of Polymers Principles and Practice (eds N.J., Everall, J.M. 

Discuss the principles of Fourier transform infrared spectroscopy and nonlinear laser optics [74, 75], and of second harmonic and sum frequency generation. Compare the relative advantages of both techniques for the study of the bonding, orientation, and location of adsorbed molecules either on metal or on insulator surfaces. 

The principles of interferometty and the operation of an FT-IR instrument are explained in two articles by W. D. Perkins Fourier Transform-Infrared Spectroscopy, Part 1 Instrumentation, Journal of Chemical Education, 63 (January 1986) A5-A10, and Fourier Transform-Infrared Spectroscopy, Part 2 Advantages of FT-IR, Journal of Chemical Education, 64 (November 1987) A269-271. 

Griffiths PR and de Haseth JA (2000) Fourier Transform Infrared Spectroscopy. 2nd edn. New York Wiley. (This is the standard book on the subject with detailed discussion of the principles of operation and design of FT-IR spectrometers.)... 

For readers interested in greater detail, Fourier transform techniques are treated in the following references (a) Marshall, A.G. Verdun, F.R. Fourier Transforms in NMR, Optical, and Mass Spectrometry Elsevier Amsterdam, 1986 (b) Griffiths, P.R., DeHaseth, J.A. Fourier Transform Infrared Spectrometry Wiley-Interseience New York, 1986 (c) Chamberlain, J. The Principles of Interferometric Spectroscopy Wiley-Interscience Chichester, 1979 (d) Bell, R. J. Introductory Fourier Transform Spectrometry Academic Press New York, 1972. 

GC-Fourier transform infrared (GC-FI IR) spectroscopy is less frequently used than GC-MS, but involves a similar principle in which the outlet from the column is coupled to an infrared spectrophotometer. The technique currently suffers from a lack of library spectra, as the IR spectra taken in the vapour phase can be subtly different from condensed phase spectra or spectra collected using the well-established KBr disc method. 

There was also described and discussed the relatively new Fourier transform infrared emission spectroscopy (IRES), its principle, an appropriate FT-IRES setup and applications. FT-IRES is unique in that it does not require an external radiation source, because the sample itself is the source. The radiation emitted from the sample is collected and sent to the detector. The ratio of the sample signal to that from a black body source represents the spectrum. However, appli-... 

The mid-infrared region of the electromagnetic spectrum starts on the higher energy at 2.5 pm (4000 cm ) and ends on the lower energy at 6 pm (650 cm ). Dispersive-type infrared absorption spectrometers have given way to Fourier-transform infrared spectrometers (FTIR). Chapter 12 of Ref. 3, or other equivalent text, should be reviewed to better understand the principles underlying infrared spectroscopy. 

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