Showing papers on "Fourier transform spectroscopy published in 1981"
TL;DR: In this article, the authors proposed a spin echo correlated spectroscopy (SECSY) technique to identify the resonances connected by a scalar spin-spin coupling in the two-dimensional Fourier transform NMR spectrum.
461 citations
TL;DR: In this article, the OD infrared spectrum, emitted in a flame of deuterium and oxygen, has been recorded for the first time in the 2-μm spectral range with a Fourier Transform spectrometer.
148 citations
115 citations
110 citations
100 citations
TL;DR: In this article, a two-dimensional Fourier transform was used to detect the relative sign of the spin coupling constants in high-resolution NMR spectra, which can be used as a diagnostic tool in the recognition of geminal and vicinal proton-proton couplings.
97 citations
TL;DR: In this paper, the application of Fourier transform infrared spectroscopy to the quantitative determination of mineral matter in coal is discussed and the use of a least squares curve-fitting program allows a choice between standards to be made.
Abstract: The application of Fourier transform infrared spectroscopy to the quantitative determination of mineral matter in coal is discussed. The use of a least squares curve-fitting program allows a choice between standards to be made. The results of an analysis of mineral mixtures and a coal low temperature ash are presented. The results are in good agreement with known concentrations and those obtained by other methods of analysis.
87 citations
TL;DR: In this paper, the first application of Fourier transform infrared spectroscopy as an analytical probe for the in situ monitoring of electrochemical interfacial phenomena is reported, where the structure of acetonitrile at the interface is reported.
81 citations
70 citations
TL;DR: In this article, the Fourier absorption spectra of HCl and DCl were recorded simultaneously in the spectral range [2840 cm−1−8450 cm− 1] and a Uij reduced Dunham coefficient set was deduced by fitting all the available data and then used together with four mass-scaling parameters to predict the TCl Yij Dunham coefficients.
68 citations
TL;DR: There is no evidence for a significant change in the conformational order at low temperatures or the liquid-crystalline phase or the phospholipid phase transition.
Abstract: Glycophorin from the human erythrocyte membrane has been isolated in pure form and reconstituted into large unilamellar vesicles with 1,2-dimyristoyl-3-sn-phosphatidylcholine at lipid/protein mole ratios ranging from 50:1 to 200:1. The effect of protein on the phospholipid phase transition has been monitored by Raman and Fourier transform infrared spectroscopy and differential scanning calorimetry. No evidence for an immobilized higher melting lipid component is observed. The gel to liquid-crystalline phas transition is significantly broadened and shifted to lower temperatures as the proportion of protein is increased, while the pretransition is abolished. At all temperatures, the mobility of the acyl chains is increased by the addition of protein while interchain lateral interactions are disrupted. However, there is no evidence for a significant change in the conformational order at low temperatures (approximately 5 degrees C) or ii the liquid-crystalline phase.
TL;DR: The basic problems of condensed phase infrared emission spectroscopy are discussed in this paper, conditions which cause instrumental background and the method for background removal are reviewed, and the sensitivity of the technique is illustrated with spectra of microgram quantities.
Abstract: The basic problems of condensed phase infrared emission spectroscopy are discussed. Conditions which cause instrumental background and the method for background removal are reviewed. The sensitivity of the technique is illustrated with spectra of microgram quantities. Spectra are shown for samples near room temperature (30°C) and for a sample below room temperature. The major limitations in infrared emission spectroscopy are reviewed and the problems associated with multiple passing of radiation through the modulator are outlined.
TL;DR: In this article, the spectrum of fluorescence excited by the 5145 nm line of a multimode Ar+ laser is recorded by a Fourier-transform spectrometer in the region 7000-7300 cm−1 (143 to 137 μm).
Abstract: The spectrum of fluorescence excited by the 5145 nm line of a multimode Ar+ laser is recorded by a Fourier‐transform spectrometer In the region 7000–7300 cm−1 (143 to 137 μm), transitions from the B 0+u state are recorded into two states, which had been previously only indirectly observed, as well as into the X 1Σ+ state Vibrational levels 0–9 for the 0+g and 0–14 for the 1g states are sampled The principal molecular constants determined are as follows: where all constants are in cm−1 except when noted, with 2σ uncertainties in parentheses
TL;DR: In this paper, the second derivative infrared spectroscopy was used for trace gas analysis and an algorithm was described for numerical differentiation of a digitized infrared spectrum. But the analysis of trace gases was performed by computing the second derivatives of the spectrum.
Abstract: The analysis of trace gases by infrared spectroscopy is enhanced by computing the second derivative of the spectrum. The peak maxima are increased for sharp bands while contributions from broad, structureless, continua are reduced. For weak absorbers the peak maxima are linear in concentration. The advantages of second derivative infrared spectroscopy in trace gas analysis are illustrated, and an algorithm is described for numerical differentiation of a digitized infrared spectrum.
TL;DR: In this article, thin tetramethylsilane (TMS) films were formed using rfglowdischarge polymerization and the films were found to be pinhole free, chemically resistant, and adherent to silicon, aluminum, and glass substrates.
Abstract: Thin films of tetramethylsilane (TMS) were formed using rf‐glow‐discharge polymerization. The films were found to be pinhole free, chemically resistant, and adherent to silicon, aluminum, and glass substrates. Electron microprobe analyses and IR Fourier transform spectroscopy (FTS) demonstrated that small concentrations of oxygen (2–6 at. %) were always incorporated into the polymer structure. Film density, refractive index, and dielectric constant were correlated with the chemical composition of the films. Capacitance‐voltage studies of metal‐polymer‐silicon structures indicated that charge trapping and polarization instabilities existed in the films, and FTS suggests that these charge effects originated at SiO and C = 0 sites. The polymer films were found to be sensitive to moisture and to oxygen. Electron transport was enhanced in films which were exposed to water vapor.
TL;DR: New line parameters of the methane spectrum have been incorporated in the AFGL compilation for the 2385-3200-cm (-1) region and were determined from data recorded at 0.01- and 0.02-cm(-1) resolution.
Abstract: A list of new methane line parameters for the 2385-3200 cm region included in the Air Force Geophysical Laboratory's compilation of molecular line parameters is presented. Line positions were determined by computer computations from Fourier transform spectrometer data using a Kitt Peak subroutine. With the exception of class IV lines, all line strengths were determined by the method of equivalent widths. Additional line strengths were measured from spectra taken at cold sample temperatures so that lower state transition energies could be determined experimentally. Observed line positions and strengths are given for 8076 absorptions with strengths greater than 3.3 x 10 to the -24 cm/molecule.
TL;DR: A visible and near-infrared Michelson interferometer has been built to perform Fourier transform photoacoustic spectroscopy and the signal-to-improvement and the performance of the spectrometer are compared with other photoac acoustic methods.
Abstract: A visible and near-infrared (0.36–3-μm) Michelson interferometer has been built to perform Fourier transform photoacoustic spectroscopy. The scanning (step and integrate) and the internal modulation are obtained with only one active element: the moving mirror holder driven by a linear motor. The signal-to-noise improvement and the performance of the spectrometer are compared with other photoacoustic methods and illustrated by various spectra.
TL;DR: In this article, rotational spectra have been assigned for the 82 Kr, 83 Kr, 84 Kr, and 86 Kr isotopic species of the KrHF and KrDF van der Waals molecules by using pulsed microwave Fourier transform spectroscopy in a Fabry-Perot cavity with a pulsed supersonic nozzle molecular source.
TL;DR: In this paper, the binding energies of three different residual donors in undoped high purity vapor phase epitaxial GaAs using the high resolution photoluminescence spectroscopy technique at temperatures ∼ 2 K were determined from the excited state transitions of excitons bound to neutral donors.
TL;DR: In this article, the data manipulation ability of a Fourier transform IR spectrometer is exploited to characterize molecular orientation in polymers, and the application of spectral subtraction to dichroic ratio determination and to the measurement of three-dimensional orientation via sample tilting and internal reflection spectroscopy is explored for nylon film samples.
Abstract: The data manipulation ability of a Fourier transform IR spectrometer is exploited to characterize molecular orientation in polymers. In particular, the application of spectral subtraction to dichroic ratio determination and to the measurement of three-dimensional orientation via sample tilting and internal reflection spectroscopy is explored for nylon film samples.
IBM1
TL;DR: In this article, the effects of apodization on band shape and resolution were studied with particular attention on intensity considerations in the computed spectrum, and the detection of weak bands in the vicinity of strong ones and false intensities due to artificial overlap of two bands which are in near proximity were addressed.
Abstract: Since the introduction of commercially available rapid scan Fourier transform IR (FT-IR) interferometers there has been a dramatic increase in both the number of laboratories which utilize FT-IR instruments on a routine basis and the number of scientific applications in which FT-IR interferometry offers advantages over conventional dispersion spectroscopy. As a result many who have come to use Fourier transform interferometers in their studies because of its throughput (Jacquinot) and multiplex (Fellgett) advantages are less familiar with the more subtle points which must be considered when a Fourier transformation of digitized information is performed. To this end a study of the effects of apodization on bandshape and resolution is presented with particular attention on intensity considerations in the computed spectrum. In particular, problems related to (1) the detection of weak bands in the vicinity of strong ones and (2) false intensities due to artificial overlap of two bands which are in near proximity are addressed.
TL;DR: In this paper, the Fourier transform infrared spectroscopy is used to study the vibrational spectrum as a function of temperature, and the combination of Fellget's advantage, high reproducibility, and high signal/noise ratio permits the precise monitoring of small spectral changes.
Abstract: Considerable information regarding the properties of systems can be gained from a study of the vibrational spectrum as a function of temperature. Fourier transform infrared spectroscopy is well suited to such studies. The combination of Fellget's advantage, high reproducibility, and high signal/noise ratio permits the precise monitoring of small spectral changes. The low level of incident energy and the small image (generally <1 mm with high sensitivity detectors) minimizes problems resulting from sample heating and temperature gradients across the sample, and the use of the transmission technique minimizes shifts in the focus on the detector as a result of thermal expansion and contraction of the sample mount.