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Showing papers on "Fourier transform infrared spectroscopy published in 1981"


Journal ArticleDOI
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


Journal ArticleDOI
TL;DR: Analysis of spectral data suggest the presence of a very nonpolar heme--Cu pocket in which the heme-CO complex is highly ordered, but inWhich the Cu-- CO complex is much more flexible, especially above 80 K.
Abstract: Carbon monoxide bound to iron or copper in substrate-reduced mitochondrial cytochrome c oxidase (ferrocytochrome c:oxygen oxidoreductase, EC 1.9.3.1) from beef heart has been used to explore the structural interaction of the a3 heme-copper pocket at 15 K and 80 K in the dark and in the presence of visible light. The vibrational absorptions of CO measured by a Fourier transform infrared interferometer occur in the dark at 1963 cm-1, with small absorptions near 1952 cm-1, and are due to a3 heme--CO complexes. These disappear in strong visible light and are replaced by a major absorption at 2062 cm-1 and a minor one at 2043 cm-1 due to Cu--CO. Relaxation in the dark is rapid and quantitative at 210 K, but becomes negligible below 140 K. The multiple absorptions indicate structural heterogeneity of cytochrome oxidase in mitochondria. The Cu--CO absorptions (vCO) are similar to those in hemocyanin--CO complexes from molluscs (vCO - 2062 cm-1) and crustaceans (vCO = 2043 cm-1). The 2062 cm-1 Cu--CO absorption of cytochrome oxidase is split into two bands at 15 K. Analysis of spectral data suggest the presence of a very nonpolar heme--Cu pocket in which the heme-CO complex is highly ordered, but in which the Cu--CO complex is much more flexible, especially above 80 K. A function for these structures in oxygen reduction is proposed.

133 citations


Journal ArticleDOI
TL;DR: Fourier transform infrared spectroscopy has been used to characterize the oxidation of a coking coal and the results demonstrate that the most important initial products of oxidation are carbonyl and carboxylic acid groups.
Abstract: Fourier transform infrared spectroscopy has been used to characterize the oxidation of a coking coal. The results demonstrate that the most important initial products of oxidation are carbonyl and carboxylic acid groups. Bands associated with carbon-oxygen single bonds, as in ethers or phenols, do not become prominent until the later stages of the oxidative process. Upon reaction with potassium in tetrahydrofuran a number of changes in the spectrum of both the oxidized and unoxidized coal become apparent. This reagent cannot be considered specific for cleavage of ether bonds, but can also lead to products usually associated with air oxidation.

100 citations



Journal ArticleDOI
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


Journal ArticleDOI
TL;DR: Fourier transform infrared spectra, including absorbance difference spectra are presented which indicate that the accepted mechanism of tertiary amine-catalyzed copolymerization of cyclic anhydrides and epoxy resins requires modification.
Abstract: Fourier transform infrared spectra, including absorbance difference spectra, are presented which indicate that the accepted mechanism of tertiary amine-catalyzed copolymerization of cyclic anhydrides and epoxy resins requires modification. Results also show that the kinetic model is complicated by the lack of steady-state concentrations of the active species. The effect of silica filler and silane coupling agents on the reaction are also examined.

86 citations


Journal ArticleDOI
01 Jun 1981-Fuel
TL;DR: In this paper, it was shown that potassium carbonate, when well dispersed on a surface of carbon prepared from polyfurfuryl alcohol, decomposes at much lower temperatures than bulk carbon carbonate.

82 citations


Journal ArticleDOI
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


Journal ArticleDOI
TL;DR: Fourier transform infrared spectroscopy has been used to study the thermotropic behavior of hydrated multibilayers of specifically deuterated derivatives of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine and it is shown that throughout the gel phase there is little or no conformational disorder introduced into the acyl chains.

79 citations


Journal ArticleDOI
01 Oct 1981
TL;DR: In this paper, the molecular structures of multiple amino coupling agents have been studied on glass surfaces and as solids using Fourier transform infrared spectroscopy, and the effects of hydrogen bonding and orientation on the adsorption mechanism are discussed.
Abstract: The molecular structures of multiple amino coupling agents have been studied on glass surfaces and as solids using Fourier transform infrared spectroscopy. High specific surface area fumed silica (Cab-O-Sil) was used. N-2-Aminoethyl-3-aminopropyltrimethoxysilane (AAPS) and trimethoxysilylpropyldiethylenetriamine (TPDT) were deposited on glass surfaces from diluted aqueous and nonaqueous solutions. From toluene solution, the hydrolyzed AAPS was adsorbed onto glass surfaces to form a completely cured coupling agent layer. From aqueous solutions, the AAPS was deposited as an incompletely cured polyaminosiloxane. The band at 940 cm−1 is assigned to the SiO stretching mode of the uncured silanols of polyaminosiloxane. The difference spectra before and after heat treatment of these samples show the disappearance of the SiOH group of coupling agent and the glass surfaces. A model of interpreting the orientation of AAPS and TPDT on the surface of silica is proposed. The infrared integrated absorbance measurements of the amount of the AAPS and TPDT on the silica suggest that the amount of adsorption depends on the concentration of solution and the nature of coupling agents. The effects of hydrogen bonding and orientation on the adsorption mechanism are discussed. The hydrothermal stability of the coupling agents on the glass surfaces are also examined by infrared spectroscopy.

68 citations



Journal ArticleDOI
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.


Journal ArticleDOI
K. Krishnan1
TL;DR: In this paper, a photoacoustic cell for use with Fourier transform infrared spectrometers is described, showing high sensitivity on a variety of chemical systems and saturation effects can play a prominent role in the photo-acoustic spectra.
Abstract: A new photoacoustic cell for use with Fourier transform infrared spectrometers is detailed. Photoacoustic infrared spectra showing high sensitivity on a variety of chemical systems are presented. Comparison of the photoacoustic infrared spectra with transmission and attenuated total internal reflectance spectra show that saturation effects can play a prominent role in the photoacoustic spectra. Spectral subtractions and study of the situ chemical reactions are possible using the photoacoustic technique. The photoacoustic and diffuse reflectance techniques yield very similar spectra.


Journal ArticleDOI
TL;DR: In this article, the authors investigated the thermal degradation behavior of poly(1,3-phenylene isophthalamide) and poly(chloro-2,4-phenylon isophalamide) with the aid of some appropriate model compounds.
Abstract: Thermal degradation behavior of poly(1,3-phenylene isophthalamide) and poly(chloro-2,4-phenylene isophthalamide) was investigated with the aid of some appropriate model compounds. The pyrolysis products of these materials were identified by gas chromatography (GC), gas chromatography/Fourier transform infrared spectroscopy (GC/FT-IR), and gas chromatography/mass spectrometry (GC/MS). The residual chars were characterized by IR spectroscopy. Thermogravimetric analysis (TGA) was applied to study the effect of end-group concentration on the degradation characteristics of the two polyamides. Kinetic parameters that describe the thermal degradation of the polyamides were also evaluated by TGA. The results of this investigation suggest that the thermal decomposition of these aromatic polyamides involves homolytic as well as hydrolytic cleavages of the amide units.



Journal ArticleDOI
TL;DR: In this article, the properties of a Fourier transform infrared (FT-IR) spectrometer designed around a polarizing Michelson interferometer (PMI) are analyzed with respect to applications in both conventional absorption as well as polarization spectroscopies.
Abstract: The properties of a Fourier transform infrared (FT-IR) spectrometer designed around a polarizing Michelson interferometer (PMI) are analyzed with respect to applications in both conventional absorption as well as polarization spectroscopies. The PMI design is that of Martin and Puplett and consists of a metal grid polarizing beam splitter combined with rooftop retromirrors set to rotate the polarization direction in each beam by 90°. If used in conjunction with additional grid polarizers, positioned according to application, the result is an FT-IR instrument that can function both as a dual beam absorption spectrometer and as a polarization spectrometer. Operating in the former mode, the instrument is predicted to achieve speeds comparable to those achievable using a nonpolarizing dual beam Michelson interferometer but to cover a much wider spectral range due to the achromatic nature of metal grid polarizing beam splitters. In the latter mode, it is predicted to give at least double the effective throughput achievable with conventional instruments equipped with external polarization modulating optics, and again to cover a much wider spectral range. It would extend the capability of determining circular dichroism spectra into the far IR (down to ∼3 cm−1) for the first time. With the development of a process for forming a metal grid polarizer of fine spacing (∼0.1 μm) on a KBr substrate, the instrument would be capable of covering the spectral range 25 000 to 3 cm−1 or lower using only two beam splitters, i.e., in two ranges: 25 000 to 450 cm−1 using a KBr-supported metal grid, and 600 to 3 cm−1 or less using an unsupported wire grid.

Journal ArticleDOI
TL;DR: Fourier transform infrared spectra have been obtained of compatible blends of polyphenylene oxide (PPO) and polystyrene (PS), and an incompatible blend of poly(4-chlorostyrene) (P4C1S) was also studied.
Abstract: Fourier transform infrared spectra has been obtained of compatible blends of polyphenylene oxide (PPO) and polystyrene (PS). An incompatible blend of polyphenylene oxide and poly(4-chlorostyrene) (P4C1S) was also studied. Factor analysis was used to determine the number of components in the blend system. The data indicated that three components existed in the PPO/PS compatible system and only two in the PPO/P4C1S system. The interaction spectrum in the compatible blend was determined by a double-subtraction technique and used to analyze the blend system for the magnitude of the interaction as a function of composition. The interaction was maximum at a 70/30 composition in agreement with other data.

Journal ArticleDOI
TL;DR: In this article, Fourier transform infrared (FT-IR) spectra of deoxyribonucleic acid (DNA) and its reaction products with the anticancer drug cis-Pt(NH3)2Cl2, cis-diamminodichloroplatinum (abbreviated cisplatin) were obtained and studied.
Abstract: Fourier transform infrared (FT-IR) spectra of deoxyribonucleic acid (DNA) and its reaction products with the anticancer drug cis-Pt(NH3)2Cl2, cis-diamminodichloroplatinum (abbreviated cisplatin) in water and heavy water solutions or gels have been obtained and studied. The mid-IR spectra show considerable changes in the carbonyl (C==O) region and weaker, but significant perturbations in the sugar-phosphate absorption region (PO2−, OPC and COP). The carbonyl bands at 1710 and 1686 cm−1 of the control DNA in H2O and D2O, respectively, disappear and shift to lower frequencies in the spectra of cisplatin + DNA with a r = Pt/P = 0.2. Furthermore, the sugar-phosphate band at 1054 cm−1 of the C—O stretching vibration of the ribose-phosphate bond is reduced in intensity and slightly shifted to higher frequencies, indicating a reorientation of the phosphate group. In addition, the P—O stretching vibration frequency at 970 cm−1 is reduced in intensity on interaction with the drug. These changes depend to some extent on the water content in the control DNA and in the cisplatin + DNA complex. The water molecules in DNA in the presence of cisplatin reorganize themselves. The attack of the platinum drug at the N7 site of the guanine molecule in DNA exerts an effect on the DNA structure through a modification of the water average configuration and its stabilizing effect on the secondary structure.

Journal ArticleDOI
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.

Journal ArticleDOI
TL;DR: In this paper, a detailed description of a system for gas chromatographic (GC) detection of matrix isolation Fourier transform infrared (FTIR) spectrometry is presented, and applications of the technique to identification of polycyclic aromatic hydrocarbon constituents of coal-derived materials are demonstrated, and quantitative aspects of the procedure are considered.
Abstract: A detailed description of a system for gas chromatographic (GC) detection of matrix isolation Fourier transform infrared (FTIR) spectrometry is presented. Substances eluting from a support-coated open tubular column are deposited directly on individual faces of a 12-sided movable gold-plated copper disk mounted within the cold head of a closed-cycle cryostat. The same gas is used as GC carrier and spectroscopic matrix gas. An optical interface, comprising beam condensing and rod optics, permits the modified cryostat head to be mounted in proximity to the sample chamber of an FTIR spectrometer. Applications of the technique to identification of polycyclic aromatic hydrocarbon constituents of coal-derived materials are demonstrated, and quantitative aspects of the procedure are considered.

Journal ArticleDOI
TL;DR: In this article, Fourier transform infrared spectroscopy has been used to study the adsorbed state of benzene (C6H6 and C6D6) on γ-alumina and alumina-supported Pt catalysts at 300 K.

Journal ArticleDOI
TL;DR: Fourier transform infrared spectroscopy was used to identify surface species on zinc oxide and a zinc-copper mixed oxide at CO pressures up to 50 atm and a temperature of 200°C as discussed by the authors.
Abstract: Fourier transform infrared spectroscopy was used to identify surface species on zinc oxide and a zinc-copper mixed oxide at CO pressures up to 50 atm and a temperature of 200°C. In situ spectra were recorded in a high-pressure cell having a short path length. Spectra of adsorbed species on both oxides indicated the presence of carbonate, carboxylate, hydride, hydroxide, and formate surface species. The spectrum of the mixed oxide at 50 atm had additional bands which were assigned to a methoxide surface species.

Journal ArticleDOI
TL;DR: In this paper, high-resolution infrared studies of isotopic ethylenes below 2000 cm −1 were conducted with a Nicolet FTIR spectrometer, and accurate vibration and rotation parameters for the v 12 fundamentals of C 2 H 4 and C 2 D 4 were determined from spectra recorded with 0.05 cm − 1 resolution.

Journal ArticleDOI
TL;DR: In this paper, the infrared spectrum of the stretching fundamentals of SiF2 has been obtained at a resolution of ≈ 0.1 cm−1 using a FTIR spectrometer.

Journal ArticleDOI
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.

Journal ArticleDOI
TL;DR: Fourier transform infrared spectroscopy has been applied to the study of polycrystalline silicon samples previously exposed to rf• and dc•induced hydrogen plasmas as discussed by the authors.
Abstract: Fourier transform infrared spectroscopy has been applied to the study of polycrystalline silicon samples previously exposed to rf‐ and dc‐induced hydrogen plasmas. The first direct observation of hydrogen incorporated in the grain boundaries has been made. Peaks attributable to surface hydrogen have also been observed. The techniques developed show considerable utility in probing the very small numbers of impurity atoms in grain boundaries.

Journal ArticleDOI
TL;DR: In this paper, the infrared emission spectrum of a monolayer quantity of chemisorbed p-nitrobenzoic acid on a thin oxide coated, evaporated copper substrate at 300 K was observed.