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Showing papers on "Fourier transform spectroscopy published in 1978"


Journal ArticleDOI
01 Jul 1978-Nature
TL;DR: Fourier Transform Infrared Spectroscopy: Applications to Chemical Systems as discussed by the authors is an application of Fourier transform infrared spectroscopy for chemical systems. But it is not suitable for biomedical applications.
Abstract: Fourier Transform Infrared Spectroscopy: Applications to Chemical Systems Vol 1 Edited by J R Ferraro and L J Basile Pp 311 (Academic: New York, San Francisco and London, 1978) $25; £1625

613 citations



Journal ArticleDOI
TL;DR: In this article, the Fourier transform was used to detect multiple quantum transitions in dipolar systems along with results on some protonated liquid crystal systems and a simple operator formalism for the essential features of the time development is presented.
Abstract: The excitation and detection of multiple quantum transitions in systems of coupled spins offers, among other advantages, an increase in resolution over single quantum n.m.r. since the number of lines decreases as the order of the transition increases. This paper reviews the motivation for detecting multiple quantum transitions by a Fourier transform experiment and describes an experimental approach to high resolution multiple quantum spectra in dipolar systems along with results on some protonated liquid crystal systems. A simple operator formalism for the essential features of the time development is presented and some applications in progress are discussed.

313 citations


Journal ArticleDOI
TL;DR: A general theory is presented for selective or “tailored” excitation by an arbitrary modulation of the radiofrequency transmitter signal, and it confirms earlier conclusions that the frequency-domain excitation spectrum corresponds to the Fourier transform of the transmitter modulation pattern.

243 citations


Book
11 Apr 1978
TL;DR: A survey of infrared data processing techniques can be found in this paper, where the authors present a survey of the state-of-the-art techniques in infrared spectroscopy, including Fourier Transform Infrared Reflection*b1Absorption Spectroscopy.
Abstract: P.C. Gillette, J.B. Lando, and J.L. Koenig, A Survey of Infrared Spectral Data Processing Techniques. P.L. Polavarapu, Fourier Transform Infrared Vibrational Circular Dichroism. K. Krishnan, Advances in Capillary Gas Chromatography*b1Fourier Transform Interferometry. A.G. Nerheim, Applications of Spectral Techniques to Thermal Analysis. P. Painter, M. Starsinic, and M. Coleman, Determination of Functional Groups in Coal by Fourier Transform Interferometry. J.R. Ferraro and A.J. Rein, Applications of Diffuse Reflectance Spectroscopy in the Far-Infrared Region. J.D. Swalen and J.F. Rabolt, Characterization of Orientation and Lateral Order in Thin Films by Fourier Transform Infrared Spectroscopy. W.G. Golden, Fourier Transform Infrared Reflection*b1Absorption Spectroscopy. J.A. Graham, W.M. Grim III, and W.G. Fateley, Fourier Transform Infrared Photoacoustic Spectroscopy of Condensed-Phase Samples. Each chapter includes references. Index.

163 citations



Journal ArticleDOI
TL;DR: In this article, a tilt-compensated triple-pass system for use with previously built Fourier spectrometers to increase the resolution by 3 is described. But the resulting width of the apparatus function of the third-generation interferometer is better than 10−3 cm−1 and can be meaningfully expressed in frequency units.
Abstract: The contribution of the third-generation Fourier spectrometer, built at the Laboratoire Aime Cotton and currently at the Laboratoire d'Infrarouge, to meteorological and high resolution Doppler-limited measurements is reported citing typical examples and the latest instrumental improvements. A tilt-compensated triple-pass system for use with previously built Fourier spectrometers to increase the resolution by 3 is described. The resulting width of the apparatus function of the triple-pass third-generation interferometer is better than 10−3 cm−1 and can be meaningfully expressed in frequency units. Its actual value is 27 MHz. For the first time a spectrometer is able to give very wide spectral range information with a resolving power sufficient to analyze sub-Doppler spectra.

59 citations



Journal ArticleDOI
TL;DR: The technique of Fourier spectroscopy, the full realization of its advantage, has been applied to a time-dependent study and the SNR expected and the instrumentation involved are discussed.
Abstract: The technique of Fourier spectroscopy, the full realization of its advantage, has been applied to a time-dependent study The principle of the technique, the SNR expected, and the instrumentation involved are discussed together with some recent results

53 citations


01 Jan 1978

45 citations


Journal ArticleDOI
TL;DR: In cases where the photon noise is the limiting factor, the multiplex gain is not always conserved; however the throughput (Jacquinot's advantage) is not affected Therefore extension of Fourier transform spectroscopy to higher frequencies has great possibilities.
Abstract: In cases where the photon noise is the limiting factor, the multiplex gain is not always conserved; however the throughput (Jacquinot's advantage) is not affected Therefore extension of Fourier transform spectroscopy to higher frequencies has great possibilities Studies at high resolution, both in emission and in absorption, show that the performance achieved by Fourier transform spectroscopy in the visible and uv range is comparable with that reached in the ir

Journal ArticleDOI
TL;DR: This paper discusses the use of Michelson interferometers in the study of transients, and new results will be presented.
Abstract: Fourier transform spectroscopy has been demonstrated to provide outstanding results in astronomical and high resolution spectral studies of cw sources. However, techniques for the study of reacting or transient systems have been less than satisfactory in cases where one is seriously interested in obtaining detailed spectroscopic data. It has been demonstrated that Fourier transform techniques can also be utilized in the study of systems which are transient as well. This paper discusses the use of Michelson interferometers in the study of transients, and new results will be presented.

Journal ArticleDOI
01 Nov 1978-Nature
TL;DR: In this paper, coherent anti-Stokes Raman spectroscopy (CARS) at low frequency shifts is discussed, where the Doppler width is proportional to the Raman shift of the band under study.
Abstract: THE techniques of coherent Raman spectroscopy are revolutionising the applications and scope of Raman spectroscopy. Particularly important aspects are: very high resolution spectroscopy (the Doppler width being proportional to the Raman shift of the band under study); nanosecond (and sub-nanosecond) spectroscopy, where the resolution obtained may be limited by the Fourier transform of the experimental time scale; discrimination against luminescence from the sample (whether laser induced or not). We discuss here coherent anti-Stokes Raman spectroscopy (CARS) at low frequency shifts.


Journal ArticleDOI
TL;DR: Four major trends will characterize the evolution of Fourier transform spectroscopy's analytical laboratory applications in the remaining seventies and early eighties: a more thorough analysis of the nonidealities of real FT-ir systems will allow the quantitative accuracy of FT-IR to approach its SNR capability, or to be corrected to this level.
Abstract: Four major trends will characterize the evolution of Fourier transform spectroscopy's analytical laboratory applications in the remaining seventies and early eighties: (1) A more thorough analysis of the nonidealities of real FT-IR systems will allow the quantitative accuracy of FT-IR to approach its SNR capability, or to be corrected to this level. (2) The power of FT methods is severely mismatched to current practice and habits in the infrared analytical laboratory. New operating procedures, combination techniques such as GCIR (a much better match to FT-IR capabilities) and more demanding spectroscopic techniques, will become more common. In the wake of this development, greater emphasis will be placed on automatic sample preparation and interpretation. (3) At the same time, the importance of spectra as the final output of spectroscopic measurements will decrease. Instead, higher order spectroscopic functions, or even final analytical data, will become a frequent instrumental output, with or without high level operator interaction. (4) The domain of application of Fourier transform spectroscopy will tee steady extension into new spectral regions, such as the near infrared and UV-VIS regions, while its extension to Raman spectroscopy still appears elusive. The analysis embodies a strong conservative bias, in that it excludes from consideration the consequences of new technology. This also insures its relevance to currently existing instrumentation.

Journal ArticleDOI
TL;DR: In this article, a commercial high resolution (0.06 cm-1) Fourier transform infrared spectrometer for use in absorption spectroscopy on a jet aircraft is described, emphasizing methods of dealing with the difficulties of the aircraft environment.
Abstract: High resolution infrared spectroscopy is a very useful technique for remote sensing of atmospheric constituents. From an aircraft it is possible to use emission or absorption spectroscopy to measure total quantities of constituents above the aircraft or profiles at altitudes below the flight. The adaptation of a commercial high resolution (0.06 cm-1) Fourier transform infrared spectrometer for use in absorption spectroscopy on a jet aircraft is described, emphasizing methods of dealing with the difficulties of the aircraft environment. Atmospheric constituents with concentrations less than one part per billion can be measured.

Journal ArticleDOI
TL;DR: In this article, the construction and operation of a Michelson interferometer that permits Fourier transform photoacoustic spectroscopy of opaque and partially transparent samples at visible wavelengths is described.
Abstract: The construction and operation of a Michelson interferometer that permits Fourier transform photoacoustic spectroscopy of opaque and partially transparent samples at visible wavelengths is described. Multiplexing and throughput advantages are considered. A visible spectrum of Nd(III) doped laser glass is reproduced and potential kinetic applications are described.

Journal ArticleDOI
01 Mar 1978
TL;DR: In this paper, the ratios of g1-factors, hyperfine structure anomalies, magnetic moments, atomic shielding constants and the ratio of the quadrupole moments are evaluated using also data from literature.
Abstract: 135Ba and137Ba Fourier transform nuclear magnetic resonance and nuclear quadrupole resonance investigations are reported in liquids resp. solids. From these measurements ratios of g1-factors, hyperfine structure anomalies, magnetic moments, atomic shielding constants and the ratio of the quadrupole moments are evaluated using also data from literature.

Journal ArticleDOI
TL;DR: The real and imaginary parts of the far-infrared refractive indices of eight materials at both 100 and 300° K were determined from amplitude and phase reflection measurements made by dispersive Fourier transform spectroscopy.

Journal ArticleDOI
TL;DR: The use of infrared methods in pollution measurement has been hampered by sensitivity limitations and by interferences from water vapor, but Fourier transform spectrometer systems reduce these limitations by their high optical efficiency and their ability to manipulate spectra for removal of interfering bands.
Abstract: The use of infrared methods in pollution measurement has been hampered by sensitivity limitations and by interferences from water vapor. Fourier transform spectrometer systems reduce these limitations by their high optical efficiency and their ability to manipulate spectra for removal of interfering bands. At the Environmental Protection Agency we have sought to further increase the sensitivity of the infrared technique by evolving optimal long path cell designs and sample concentration techniques. Reactive pollutants such as O(3), H(2)O(2), HNO(3), HNO(2), H(2)CO, HCOOH, PAN, HCl, NH(3), NO, and NO(2) are best measured in the open atmosphere. In this case one strives toward large absorption cells with the paths as long as practical. Our largest cell is being used to measure pollutants in the smog at Riverside, California. This cell uses an eight-mirror system for multiple-passing radiation along a 23-m base path, yielding total paths measured in kilometers. Reactive gases at levels of just a few ppb have been measured. For measuring nonreactive pollutants, such as hydrocarbons and halocarbons, maximum detection sensitivity is achieved with small folded-path cells rather than with large cells. In this case a pollutant concentrate is prepared and introduced into a miniaturized multiple-pass cell designed for maximum path-to-volume ratio. Cryogenic trapping to separate the pollutants from the major constituents of the air has yielded concentration factors as high as one million. The smallest multiple-pass cell we have built to date encloses a 115-cm light path within a volume of 3 cm(3). This cell when used with the FTS spectrometer and mercury-cadmium-telluride detector permits the detection of nanogram quantities of pollutant gases. Measurements have been made of trace gases in the air at mixing ratios as low as 2 x 10(-11).



Journal ArticleDOI
TL;DR: In this article, the opto-acoustic effect has been used in rapid scan Fourier spectroscopy to obtain directly the absorption lines of the gas contained in the spectrophone cell.


Journal ArticleDOI
L. Genzel1, J. Kuhl1
TL;DR: In this article, a Michelson interferometer for double-beam differencing Fourier spectroscopy is described, which uses only one source and one detector, but an input and an output beam-splitter allows combination of the two normal and two antiphase interferograms in various ways to achieve compensation of the a.c. and d.c parts.


Journal ArticleDOI
TL;DR: In this article, a Michelson interferometer system capable of Fourier transform spectrochemical measurements from the uv to the midir has been developed in a laboratory using phase-locked loop techniques.
Abstract: A versatile Michelson interferometer system capable of Fourier transform spectrochemical measurements from the uv to the midir has been developed in our laboratory. Laser fringe referencing is used in the interferometer system to sequence digitization and the velocity of the air bearing mirror drive system is controlled with the laser fringe signal using phase-locked loop techniques. Interferograms can be time averaged under white light interferogram control. The modular design of the interferometer is such that the detector, beamsplitter, and source can all be changed and the interferometer realigned in a matter of a few minutes. Interferograms are acquired and transformed with a PDP 11 minicomputer. This system is described in detail and its application to spectrochemical measurements in the mid-ir and uv-visible is briefly illustrated.

Journal ArticleDOI
TL;DR: The theoretical sensitivity of a Fourier transform infrared spectrometer as measured by the signal/noise ratio of a 100% line is calculated in this paper, and the theoretical expected sensitivity is shown to be in excellent agreement with experimental values observed for a particular Spectrometer configuration.
Abstract: The theoretical sensitivity of a Fourier transform infrared spectrometer as measured by the signal/noise ratio of a 100% line is calculated. This theoretically expected sensitivity is shown to be in excellent agreement with experimental values observed for a particular spectrometer configuration. The experimental method used to quantify the performance level of the spectrometer may also be applied as a general systems test for Fourier transform infrared spectrometers.


Journal ArticleDOI
TL;DR: Fourier transform spectroscopy as discussed by the authors is a technique that uses interference of light rather than dispersion to measure the spectrum of a substance, and is based on the Fourier-pair relationship between the interferogram (interference function) of the substance and its spectrum.
Abstract: Fourier transform spectroscopy is a technique that uses interference of light rather than dispersion to measure the spectrum of a substance. The basis of this technique is the Fourier-pair relationship between the interferogram (interference function) of a substance and its spectrum. This relationship and other important physical and mathematical principles of Fourier transform spectroscopy are reviewed, and the important role of mini-computers in the development and application of this technique is discussed.