Showing papers on "Fourier transform spectroscopy published in 1979"
01 Aug 1979
421 citations
TL;DR: In this article, the principles of interference spectroscopy have been discussed in terms of interferometric Spectroscopy, and the authors propose a method for interferometry in spectroscopic spectra.
Abstract: (1979). The Principles of Interferometric Spectroscopy. Optica Acta: International Journal of Optics: Vol. 26, No. 12, pp. 1449-1449.
176 citations
TL;DR: In this article, the rotational transitions of weak molecular complexes were observed by combining the techniques of microwave Fourier transform spectroscopy, a Fabry-Perot cavity, and a pulsed nozzle source of molecules.
Abstract: A new method of observing the rotational transitions of weak molecular complexes by combining the techniques of microwave Fourier transform spectroscopy, a Fabry–Perot cavity, and a pulsed nozzle source of molecules is described. High resolution and good sensitivity are achieved. Twelve isotopic species of the KrHCl molecule involving all combinations of the 86Kr, 84Kr, 82Kr, H, D, 35Cl, and 37Cl isotopes are assigned and the rotational constants, Cl nuclear quadrupole coupling constants, and centrifugal distortion constants are all given. The molecular structure indicates a linear equilibrium structure with the H(D) atom between the Kr and Cl atoms. However, the inverse moments of inertia measured here indicate large amplitude vibrations of the H(D) atom relative to the Kr–Cl internuclear line. Estimates of the Kr–Cl stretching frequency and force constants, which show considerable dependence on the isotopic species, are also given. Bending frequencies and force constants are also given.
175 citations
162 citations
159 citations
104 citations
TL;DR: In this article, a general method for direct measurement of differential absorption intensities using a Fourier transform infrared spectrometer is described, and specific expressions are presented for the measurement of circular and linear dichroism.
Abstract: A general method for the direct measurement of differential absorption intensities using a Fourier transform infrared spectrometer is described. The differential intensities must be higher in frequency than the interferogram frequencies and may arise from a periodic variation of the absorption strength of the sample, or by dichroic response of the sample to alternate states of polarization of the infrared beam. Specific expressions are presented for the measurement of circular and linear dichroism. These expressions represent an extension of the Grosjean-Legrand polarization modulation technique to Fourier transform interferometry.
94 citations
TL;DR: The feasibility of applying the methods of factor analysis to Fourier transform infrared spectra is examined in this article, where the method is designed to determine the number of components contributing to a spectral region.
Abstract: The feasibility of applying the methods of factor analysis to Fourier transform infrared spectra is examined. The method is designed to determine the number of components contributing to a spectral region. The technique has been applied to a model system consisting of solutions of p-, o-, and m-xylenes. The method has also been used for calculating the number of independently absorbing species in several polymer systems. Spectral requirements and the general applicability of factor analysis are also discussed.
78 citations
70 citations
TL;DR: Fourier transform infrared transmission spectroscopy is presented as a technique with great potential for the study of aqueous membrane preparations and the methodology of sample preparation, spectra recording and data reduction is outlined.
68 citations
TL;DR: The use of combined gas-liquid chromatography and infrared spectroscopy (GC/IR) has seen a marked increase in interest in the use of GC/IR in the past few years.
Abstract: The past few years have seen a marked increase in interest in the use of combined gas-liquid chromatography and infrared spectroscopy (GC/IR). This increase in interest is primarily due to the advent of Fourier transform infrared spectroscopy (FTIR). The combination. GC/FTIR. provides the sensitivity and scanning speed which have hindered the wide applicability of GC/IR using dispersive instruments.
TL;DR: In this paper, a numerical deconvolution procedure was used to produce amplitude-corrected, phasecorrected absorption-mode Fourier transform ion cyclotron resonance (FT ICR) spectra.
TL;DR: For spectral lines with combined Doppler and pressure broadening, the Fourier transform of the line shape is calculated analytically in an isothermal layer in which both the pressure and absorber concentrations vary along the line of sight.
Abstract: For spectral lines with combined Doppler and pressure broadening, the Fourier transform of the line shape is calculated analytically in an isothermal layer in which both the pressure and absorber concentrations vary along the line of sight. Use of the Cooley-Tukey fast Fourier transform algorithm allows efficient computation of the optical depth of such layers containing a large number of absorption lines of the same shape. The computation time is almost independent of the number of absorption lines. In many cases, this method allows increased speed and accuracy compared with conventional line-by-line methods.
TL;DR: A new method for surface roughness measurements is described based on the fibrous, roughness-dependent structure of polychromatic speckle patterns in the far field, which calculates the theoretical roughness dependence of a parameter in the Fourier spectrum.
Abstract: A new method for surface roughness measurements is described based on the fibrous, roughness-dependent structure of polychromatic speckle patterns in the far field. The patterns are recorded on photographic film and analyzed by an optical Fourier transform system with a double aperture in the film plane. We have calculated the theoretical roughness dependence of a parameter in the Fourier spectrum. Our experimental results agree fairly well with the theory.
TL;DR: In this paper, Fourier transform spectroscopy has been used for the characterisation of the excited state, B 1u, of an argon-ion laser in a complex spectrum.
Abstract: Fluorescence of 130Te2 and 128Te2 excited by lines of an argon-ion laser have been recorded by Fourier transform spectroscopy. The resolution and precision afforded by this technique has enabled several new features of this complex spectrum to be observed for the first time, including the characterisation of the excited state, B 1u. It is concluded that this is a method of some general utility.
TL;DR: In this article, the emission spectrum of the 14 N 16 O and 15 n 16 O molecules has been recorded with a high-resolution Fourier interferometer (resolution 14 × 10 −3 cm −1 ) in the 7000-10 000 cm−1 spectral range.
TL;DR: A bibliography of 112 source publications and 20 review articles and books containing information on the technique of dispersive Fourier transform spectrometry (DFTS) and its application to the study of gases, liquids and solids is presented in this paper.
TL;DR: In this article, the matrix analysis of neutron spin-echo is extended to the general case of an asymmetric spectrometer configuration, and an integral transform of the incident or scattered beam spectrum is measured by scanning the asymmetry, defined as the difference between the number of precessions in the two arms.
Abstract: The matrix analysis of neutron spin-echo is extended to the general case of an asymmetric spectrometer configuration. It is shown that an integral transform of the incident or scattered beam spectrum may be measured by scanning the asymmetry, defined as the difference between the number of precessions in the two arms. The problem of inverting the integral transform is considered, and we show how the fast Fourier transform technique may be used as the basis for an efficient numerical solution. Experimental results confirming the calculation are presented. Since only a few precessions of asymmetry are needed to measure the spectrum of a broad incident beam, the technique provides a simple means of spectral analysis suitable for use on medium flux reactors.
TL;DR: In this paper, it was shown that nonreactive ion-molecule collision frequencies can be determined either by analysis of the transient signal resulting from excited ion cyclotron motion or by linewidth measurement of the Fourier transform of the signal.
TL;DR: In this article, rotational constants have been found which reconstruct the dominant Q-branch lines up to J = 78, which is in fair agreement with the Fourier transform spectra from 925 to 935 cm 1 recorded at a resolution of 0.04 cm-1.
Abstract: The spectral region near 923 cm-1 is studied by using diode laser spectra of the dominant Q-branch belonging to the CF2 35Cl2 molecule along with Fourier transform spectra of the entire region from 910 to 935 cm-1. The overlap of the many absorption bands and also the large density of lines make quantum identification difficult because even at the resolving power of the diode laser (0.001 5 cm-1) the lines observed are not pure. However, rotational constants have been found which reconstruct the Q-branch lines up to J = 78. The profile of the R-branch calculated from these constants is in fair agreement with the Fourier transform spectra from 925 to 935 cm-1 recorded at a resolution of 0.04 cm-1.