Showing papers on "Fourier transform infrared spectroscopy published in 1989"
TL;DR: The environment of carbonate ions in bones of different species was investigated by Fourier Transform Infrared Spectroscopy associated with a self-deconvolution technique and a band not previously observed was shown to correspond to a labile carbonate environment.
Abstract: The environment of carbonate ions in bones of different species (rat, rabbit, chicken, cow, human) was investigated by Fourier Transform Infrared Spectroscopy (FTIR) associated with a self-deconvolution technique. The carbonate bands in thev
2 CO
3
2−
domain show three components which were identified by using synthetic standards and different properties of the apatitic structure (ionic affinity for crystallographic locations, ionic exchange). The major component at 871 cm−1 is due to carbonate ions located in PO
4
3−
sites (type B carbonate). A band at 878 cm−1 was exclusively assigned to carbonate ions substituting for OH− ions in the apatitic structure (type A carbonate). A band at 866 cm−1 not previously observed was shown to correspond to a labile carbonate environment. The intensity ratio of type A to type B carbonate appears remarkably constant in all bone samples. The 866 cm−1 carbonate band varies in its relative intensity in different species.
595 citations
TL;DR: In this paper, it was shown that at low concentrations, Cd2+ binds primarily on PO2−, through a pure electrostatic interaction, followed by a cooperative coordination on both guanine and adenine 1 when large amounts of Cd(II) are present.
197 citations
TL;DR: It is shown here that Fourier transform infrared spectroscopy provides a rapid, convenient method for detecting lipid phase transitions in intact cells and that the transitions can nevertheless be detected in other intact cells, including those of four plant species and sperm of three animals.
179 citations
TL;DR: In this paper, reversible and irreversible interactions between ammonia and poly(pyrrole) have been studied using electrical conductivity measurements, optical spectroscopy, Fourier transform infrared spectrograms, X-ray photoelectron spectroscopic (XPS) and elemental analysis.
166 citations
TL;DR: In this paper, the pH-induced conformational transitions which occur with poly( l -lysines) of varying molecular weight were performed in aqueous media under conditions believed from previous CD studies to induce the polypeptide to adopt a particular type of secondary structure.
165 citations
TL;DR: In this paper, the authors investigated the spectral properties of thin films of polymethylmethacrylate (PMMA) and showed that during the incubation with 248 nm excimer laser light or continuous (cw) UV light sources, PMMA exhibits a rapidly increasing, broad UV absorption.
Abstract: Ultraviolet and Fourier transform infrared (FTIR) spectroscopic experiments with thin films of polymethylmethacrylate (PMMA) are reported. During the incubation with 248 nm excimer laser light or continuous (cw) UV light sources PMMA exhibits a rapidly increasing, broad UV absorption. This is caused by the production of unsaturated species, which are detected in the infrared spectrum of irradiated PMMA films. The spectral data explain the incubation process preceding the ablation of PMMA at 248 nm. Taking advantage of the increased UV absorption, cw light incubated PMMA films can be selectively ablated by standard 308 nm excimer laser pulses.
142 citations
TL;DR: Etude de la structure superficielle de l'hydroxy-apatite apres traitement thermique et adsorption d'eau.
Abstract: Etude de la structure superficielle de l'hydroxy-apatite apres traitement thermique et adsorption d'eau
138 citations
TL;DR: Some recent studies on the application of FTIR spectroscopy to the investigation of the structure and function of lipids, polypeptides and protein are reviewed in this paper.
106 citations
TL;DR: In this paper, the retention mechanism in reversed-phase liquid chromatography for large polycyclic aromatic hydrocarbons was investigated and the effects of changing the mobile phase composition and column temperature were evaluated.
83 citations
TL;DR: In this paper, the capabilities and limitations of Fourier transform infrared spectroscopy for the identification of natural resins used in historic furniture finishes are discussed. But the limitations of the Fourier transformation are not discussed.
Abstract: Infrared spectroscopy is a valuable method for the detection and identification of organic coating materials. The vibrational bands that appear in the infrared spectra provide information on chemical functional groups of a sample which may allow for general characterization of the material or even the identification of specific compounds. Mixtures of natural materials, as are often found in furniture finishes, can stretch conventional infrared spectroscopy to its limits as an analytical method. This paper outlines the capabilities and limitations of Fourier transform infrared spectroscopy for the identification of natural resins used in historic furniture finishes.
79 citations
TL;DR: The current work demonstrates the ability of infrared spectroscopy to obtain structural information on the surfactant in physical states that directly relate to those in vivo.
Book•
01 Dec 1989
TL;DR: In this article, the selective oxidation of n-pentane on 12-molybdovanadophosporic acids with 0, 1, 2, and 3 vanadium atoms was studied and compared with the behaviour of vanadyl pyrophosphate.
TL;DR: The results indicate that the etching process involves a Si(II) intermediate which can disproportionate to form a hydrogenated amorphous silicon overlayer which builds up progressively as photoetching proceeds.
Abstract: : The application of electrochemically modulated infrared spectroscopy has been particulary rewarding in the case of the metal/electrolyte interface, but there have been surprisingly few attempts to extend the method to the semiconductor/electrolyte interface. We have taken an approach which exploits the fact that in the case of a semiconductor the surface density of minority carries can be perturbed at constant potential by illumination. In this way it should be possible to modulate the rate of the surface reactions involved in photoetching and hence to detect the vibrational spectra of intermediate species. The illuminated n-Silicon/aqueous Ammonium Fluoride interface has been studied by attenuated reflectance infrared spectroscopy under conditions in which photoetching occurs. An anomalously strong Si-H stretch band was observed to develop in the region of 2100/cm when the silicon was illuminated. The intensity of the band was found to increase linearly with time under steady illumination, rapidly exceeding values corresponding to monolayer hydrogen coverage. The absorbance decayed slowly in the dark. The results indicate that the etching process involves a Si(II) intermediate which can disproportionate to form a hydrogenated amorphous silicon overlayer which builds up progressively as photoetching proceeds.
TL;DR: In this article, the formation of CCH in photodissociation of C2H2 at 193 nm was studied using time-resolved Fourier transform infrared (FTIR) emission.
Abstract: Time‐resolved Fourier transform infrared (FTIR) emission is used to study the formation of CCH in the photodissociation of C2H2 at 193 nm. Excitation of C2H2 at 193 nm is known to populate the 10ν3 level of the trans–bent electronically excited state of acetylene, which undergoes decomposition. State‐resolved infrared emission is obtained from the CCH radicals that are produced. Only vibronic levels which originate or borrow oscillator strength from the low‐lying electronically excited state of CCH, A 2Π, are observed in this study. The relative intensities of these bands are measured and the rotational state distribution for the A(010) state is obtained. The observed average rotational energy of CCH is ∼156 cm−1, which is less than the average rotational energy of the acetylene precursor. A kinematic model which can account for a rotational cooling effect in the A(010) state is described. The model incorporates the angular momentum generated by the impulsive kick due to the release of the H atom and t...
TL;DR: In this paper, the infrared spectra of the as-received monomer and the plasma polymerized monomer were compared by Fourier transform infrared spectroscopy to reveal a conversion of the primary amine in the monomer (CH2NH2) to an imine (CHNH) and a nitrile (CN), suggesting that this polymerization scheme may be typical of primary amines.
Abstract: The plasma polymerization of allylamine in an inductively coupled rf plasma reactor is analyzed by Fourier transform infrared spectroscopy. Comparison of the infrared spectra of the as-received monomer and the plasma polymerized film reveals a conversion of the primary amine in the monomer (CH2NH2) to an imine (CHNH) and a nitrile (CN). Plasma polymerization of ethylenediamine yields the same results, suggesting that this polymerization scheme may be typical of primary amines. Increasing the plasma power seems to increase the proportion of nitrile groups in relation to the imine groups. The infrared spectra of the vapor phase polymerized monomer was similar to that of the substrate-grafted allylamine film implying a similar structure. Aging of this vapor phase polymer at 120°C for 1 h in vacuum and at 295°C for 15 min in an oxygen free environment reveals nitrile group reaction similar to that observed in polyacrylonitrile. Thermogravimetric analyses of the vapor phase polymers in a nitrogen atmosphere at 20°C/min demonstrated the thermal stability, with the polymer produced at a plasma power level of 50 W retaining 20% of its weight at 1000°C. This was better than the stability shown by the polymer produced at 150 W and is attributed to the ease of nitrile group polymerization in the former.
Book•
11 Dec 1989
TL;DR: In this article, an up-to-date reference source for those familiar with chromatography/Fourier transform infrared spectroscopy (FT-IR) methods is provided.
Abstract: This book is intended to serve as an up-to-date reference source for those familiar with chromatography/Fourier transform infrared spectroscopy (FT-IR) methods and as an introduction to techniques and applications for those interested in future uses for chromatography/FT-IR.
TL;DR: In this paper, surface-enhanced Raman spectra (SERS) on copper and gold metal colloids were obtained with a Fourier transform Raman Spectrometer using a Nd:YAG laser (1.064 μm).
Abstract: Near-infrared (NIR) surface-enhanced Raman spectra (SERS) on copper and gold metal colloids were obtained with a Fourier transform Raman spectrometer using a Nd:YAG laser (1.064 μm) for excitation. Enhanced spectra were observed for pyridine and 3-chloropyridine (CP) on copper colloids and for tris(orthophenanthroline)ruthenium(II), Ru(o-phen)32+, on copper and gold colloids. The copper-colloid surface-enhanced Raman spectra of pyridine and CP were compared with spectra measured for these molecules on copper electrodes. NIR-SERS enhancements on the metal colloids were at least as large as for visible-wavelength excited SERS. Good-quality spectra of Ru(o-phen)32+ were obtained at solution concentrations as low as 0.025 mM.
TL;DR: In this article, the prototype of an infrared spectroscopic ellipsometer using a Fourier transform PC-based infrared spectrometer is described, and several applications in thin-film characterization are given, particularly in the case of bulk substrate, thick-layered materials, and determination of the dielectric function of layered materials such as silicon oxide and silicon nitride.
Abstract: The prototype of an infrared spectroscopic ellipsometer using a Fourier transform PC‐based infrared spectrometer is described. Several applications in thin‐film characterization are given, particularly in the case of bulk substrate, thick‐layered materials, and determination of the dielectric function of layered materials such as silicon oxide and silicon nitride. The sensitivity and possible improvements of this technique are discussed.
TL;DR: In this article, it was shown that the interaction of cobalt and copper in CoCu-based catalysts results in a surface CoCu alloy, which is responsible for the orientation of the CO + H2 reaction towards higher alcohols, probably via a dual-site mechanism involving both Co and Cu of the alloy.
Abstract: As evidenced from magnetic measurements and FTIR spectroscopy of CO, the interaction of cobalt and copper in CoCu-based catalysts results in a surface CoCu alloy. It is proposed that this alloy is responsible for the orientation of the CO + H2 reaction towards higher alcohols, probably via a dual-site mechanism which involves both Co and Cu of the alloy.
TL;DR: A variety of applications of the technique of Fourier transform (FT) Raman spectroscopy using a near-infrared laser excitation source have now begun to emerge.
Abstract: A variety of applications of the technique of Fourier transform (FT) Raman spectroscopy using a near-infrared laser excitation source have now begun to emerge The design and construction of a bench-top, analytical-grade FT Raman spectrometer are described Its specifications are explained and its performance and convenience of use are reported A variety of analytical applications of the FT Raman technique have been surveyed to demonstrate the versatility of the spectrometer
TL;DR: Fourier transform infrared (FTIR) spectra of nitrogen dioxide layers deposited at various rates and substrate temperatures, are reported in this article, where bands assignable to N2O4(D2h) (ordered and disordered layers), to O=N-O-NO2 ‘D’ and ‘ D’, to NO+NO−3 nitrosonium nitrate and to the NO2 monomer were observed.
Abstract: Fourier transform infrared (FTIR) spectra of nitrogen dioxide layers deposited at various rates and substrate temperatures, are reported. Bands assignable to N2O4(D2h) (ordered and disordered layers), to O=N–O–NO2 ‘‘D’’ and ‘‘D’’’ isomers, to NO+NO−3 nitrosonium nitrate and to the NO2 monomer were observed. The relative amounts of species depends upon deposition conditions. Temperature cycling effects were followed up to 205 K. Solid N2O4(D2h) behaves like a normal, stable molecular solid, its disordered layer exhibiting small frequency shifts, but also being stable with respect to temperature cycling. The observation of NO+NO−3 bands is related to the existence of the D’ isomer and of monomeric NO2. Raman experiments overemphasize the NO+NO−3 form due to resonant enhancement.
TL;DR: In this article, the capabilities of a step-scan Fourier transform spectrometer for obtaining time-resolved spectra from a pulsed fluorescent lamp are reported. But the authors focus on the potential of the stepscan interferometry for time-resolution infrared measurements of a variety of transient phenomena.
Abstract: The capabilities of a step-scan Fourier transform spectrometer of obtaining time-resolved spectra are reported. As a demonstration of the method, time-resolved spectra from a pulsed fluorescent lamp are presented. The potential of step-scan interferometry for time-resolved infrared measurements of a variety of transient phenomena is discussed.
TL;DR: It is concluded that transmission infrared spectroscopy can be employed as a technique to study the molecular surface composition of freeze-dried microorganisms.
TL;DR: In this article, small, clear Southern pine samples were treated with six different preservative solutions (Cr, Cr/Cu; Cr/As; CCA-A; CrCA-B; Cr CA-C), at 6.4 and 40 Kg/m3 retentions, compared to water treated and untreated controls.
Abstract: Although chromated copper arsenate (CCA) is one of the most important treatment methods for the prevention of decay in wood, the nature of wood/CCA reactions are not clear. The current study was undertaken to elucidate the nature of chemical reactions occurring between the components of the treating solution and the constituents of wood. Small, clear Southern pine samples were treated with six different preservative solutions (Cr; Cr/Cu; Cr/As; CCA-A; CCA-B; CCA-C), at 6.4 and 40 Kg/m3 (0.4 and 2.5 pcf) retentions, and compared to water treated and untreated controls. Samples were dried following treatment and analyzed by diffuse reflectance Fourier transform infrared spectroscopy (DRIFT). Evaluation of DRIFT data indicated that the preservative components reacted with the aromatic and carbonyl groups in wood.
TL;DR: Fourier transform infrared spectroscopy has been applied to the study of the secondary structure of the Ca2+-ATPase of sarcoplasmic reticulum and an attempt is made to quantitatively assess the various secondary structures present.
TL;DR: In this paper, the infrared spectrum of CH 3 OH between 950 and HOOcm −1 has been measured by a high resolution Fourier transform spectrometer, and a catalog of 3410 assigned lines is presented, as well as the Taylor development tables for evaluating the energies of the upper levels of the corresponding transitions.
TL;DR: In this article, the infrared fluorescence spectrum from the C-H stretch modes of vibrationally excited azulene (C10H8), a PAH was measured in the laboratory.
Abstract: The infrared fluorescence spectrum from the C-H stretch modes of vibrationally excited azulene (C10H8), a PAH was measured in the laboratory. PAHs are candidates as carriers of the unidentified infrared emission bands that are observed in many astronomical objects associated with dust and ultraviolet light. In the present experiment, gas phase azulene was excited with light from a 308 nm pulsed laser, and the infrared emission spectrum was time-resolved and wavelength-resolved. Moreover, the infrared absorption spectrum of gas phase azulene was obtained using an FTIR spectrometer. The laboratory emission spectrum resembles observed infrared emission spectra from the interstellar medium, providing support for the hypothesis that PAHs are the responsible carriers. The azulene C-H stretch emission spectrum is more asymmetric than the absorption spectrum, probably due to anharmonicity of levels higher than nu = 1. 36 refs.