Showing papers on "Fourier transform spectroscopy published in 1970"
TL;DR: In this paper, the authors analyzed the effect of different spin-echo methods on the performance of 13C spectroscopy and found that among them, the most effective is likely to be a spin echo method in which a 90° pulse is applied at the maximum of an even-numbered echo.
148 citations
TL;DR: In this article, the Fourier transform spectrometer has been used for the study of broad absorptions such as occur in liquids below 100 cm-1. But the results for water, aniline, 1,4-dioxan, cyclohexane, decahydronaphthalene, dimethyl acetylene (2-butyne) and 1-octyne are reported and considered in relation to earlier microwave dielectric data and far infra-red measurements.
Abstract: An assessment of the Fourier transform spectrometer indicates the advantages to be gained from its application to be the millimetre-wave region (10 to 2 cm–1). The attainable resolving power is adequate for the study of broad absorptions such as occur in liquids below 100 cm–1. With a mercury arc source, appropriate beam dividers, and an indium antimonide detector at 1 K, continuous refraction (n) and absorption (α) spectra have been obtained below 50 cm–1(to 2 cm–1 in some cases) for some typical polar and non-polar liquids.
Results for water, aniline, 1,4-dioxan, cyclohexane, decahydronaphthalene, dimethyl acetylene (2-butyne) and 1-octyne are reported and considered in relation to earlier microwave dielectric data and far infra-red measurements. Water and aniline show strong, almost featureless, absorptions which are probably due to the superposition of three or four processes. The non-polar and weakly-polar liquids show much smaller absorptions : 1.4 dioxan has a profile consistent with a zero permanent electric dipole moment; 2-butyne and 1-octyne show α rising linearly with over the range 5-50 cm–1. The origin of the absorption in non-polar liquids is different from the dominant mechanism in polar liquids although the peak values for both lie in the submillimetre-wave regions. The non-polar absorption peaks occur at frequencies which correlate with those calculated for molecular collisions in the liquids using the formulations of Mie and Bradley.
77 citations
50 citations
48 citations
TL;DR: In considering this technique of spectroscopy, it is interesting and useful to begin with Michelson's "visibility curves"; briefly outlining the basis of Fourier Transform spectroscopic, and then to take a giant step in terms of time and technology.
Abstract: Fourier Transform spectroscopy is beginning to flourish. However, unlike the almost explosive growth following a discovery in some fields, such as gas chromatography or lasers, the use of scanning interferometer systems to measure spectra has had to pass through a long period of quiescence. The latter was, essentially, enforced through the lack of technology, and it was the emergence of electronics and computer science that made Fourier Transform spectroscopy feasible. Further advances in technology, especially the recent advent of the minicomputer, are now rapidly raising Fourier Transform spectroscopy from obscurity. The success story, then, goes back for three quarters of a century (or even further, if one thinks of Robert Boyle's observation in t663 of what are now termed \"Newton's Rings\" Et~ and Fizeau's use of interference to study the yellow sodium doublet ~2~). In considering this technique of spectroscopy, it is interesting and useful to begin with Michelson's \"visibility curves\"; briefly outlining the basis of Fourier Transform spectroscopy, and then to take a giant step in terms of time and technology.
39 citations
33 citations
24 citations
TL;DR: In this article, Fourier transform spectroscopy was used to measure the optical absorption in the region 20−100 cm−1 for pure liquids of the ortho and meta isomers of difluoro, dichloro, and dibromobenzene at a temperature of 20°C.
Abstract: The optical absorption in the region 20–100 cm−1 has been measured by Fourier transform spectroscopy for the pure liquids of the ortho and meta isomers of difluoro‐, dichloro‐, and dibromobenzene at a temperature of 20°C. The absorptions are very broad having half‐widths of about 80 cm−1 and the peak value of the absorption coefficient is higher than that predicted by the Debye theory of dielectric relaxation for all the substances studied. The theories proposed for absorption in the far‐infrared region are inadequate and do not explain the experimental results. It is concluded that the strong absorption is predominantly due to the rotational transitions of the molecule and that a similar phenomenon should occur in all polar liquids.
21 citations
TL;DR: The first Fourier transform NMR spectrometers were available commercially for only about six years, but in this short period of time many advances and improvements in instrumentation have been made as mentioned in this paper.
Abstract: Modern Fourier transform (FT) NMR spectrometers have been available commercially for only about six years, but in this short period of time many advances and improvements in instrumentation have been made. The first FT-NMR instruments were conventional, continuous wave (CW) spectrometers to which a pulsed RF transmitter, a modified receiver-detector system, a signal-averaging device, and a small minicomputer were attached. It is not too surprising that all of the early FT instruments were quite expensive ($100,000 to $200,000), difficult to operate, fraught with numerous operating problems, and not very reliable.
21 citations
17 citations
TL;DR: In this article, Fourier transform techniques were used to sharpen the lines of the Mossbauer spectra and obtain a substantial improvement in the resolution of the spectra, which is not possible with lifetime broadening.
TL;DR: In this article, far infrared Fourier transform spectroscopy has been employed to study the Zeeman splitting of the 1 s to 2 p shallow donor impurity transition in CdTe.
TL;DR: The principles of derivative spectrophotometry have been known for many years, and a variety of instrumentation for producing the first and higher differentials of absorption spectra has been described as mentioned in this paper, but despite the advantages of the techniques for intensifying minor changes in spectra, the separation of overlapping bands, or for band sharpening, derivative traces have not been used to a significant extent in infrared spectroscopy.
Abstract: The principles of derivative spectrophotometry have been known for many years, and a variety of instrumentation for producing the first and higher differentials of absorption spectra has been described1–21 However, despite the advantages of the techniques for intensifying minor changes in spectra, the separation of overlapping bands, or for band sharpening, derivative traces have not been used to a significant extent in infrared spectroscopy
TL;DR: In this article, Fourier transform spectroscopy was used for measuring the Brillouin spectra of CS2 light scattered by CS2 and the Michelson fringe visibility was measured at selected interferometer path-length differences, and the data were interpreted to give a very accurate value of hypersonic velocity and a rough value for the line width.
Abstract: The method of Fourier-transform spectroscopy is investigated for the purpose of measuring Brillouin spectra. Initial results are presented for light scattered by CS2. The Michelson fringe visibility was measured at selected interferometer path-length differences, and the data were interpreted to give a very accurate value of hypersonic velocity and a rough value for Brillouin line width.
01 Jan 1970
TL;DR: In this article, a small modular Fourier spectrophotometer system comprised of a Michelson interferometer for the wavenumber region 10 − 500 cm−1 and a Lamellar Grating Interferometer (LGI) for the 3 − 80 cm −1 region is described.
Abstract: The properties and theory of the Fourier transform technique as applied to far-infrared spectroscopy, have been briefly reviewed. The main features of a small modular Fourier spectrophotometer system comprised of a Michelson interferometer for the wavenumber region 10 − 500 cm−1 and a Lamellar Grating Interferometer for the 3 − 80 cm−1 region are described.