Showing papers on "Fourier transform infrared spectroscopy published in 1994"
TL;DR: A fundamental microkinetic model is proposed, which accounts for the observed industrial kinetics performance and suggests a catalytic cycle that consists of both acid and redox reactions and involves both surface V-OH (Brønsted acid sites) and V=O species.
Abstract: The selective catalytic reduction reaction of nitric oxide bv ammonia over vanadia-titania catalysts is one of the methods of removing NOx pollution. In the present study, it has been possible to identify the reaction mechanism and the nature of the active sites in these catalysts by combining transient or steady-state in situ (Fourier transform infrared spectroscopy) experiments directly with on-line activity studies. The results suggest a catalytic cycle that consists of both acid and redox reactions and involves both surface V-OH (Bronsted acid sites) and V=O species. A fundamental microkinetic model is proposed, which accounts for the observed industrial kinetics performance.
612 citations
TL;DR: In this paper, the correlation between the electrochemical properties of Li carbon intercalation electrodes and their surface chemistry in solutions was investigated, and it was shown that the surface chemistry of these electrodes is surface film controlled.
Abstract: The correlation between the electrochemical properties of Li carbon intercalation electrodes and their surface chemistry in solutions was investigated. The carbons investigated were primarily graphite and petroleum coke, and the solvent systems included methyl formate (MF), propylene and ethylene carbonates, ethers and their mixtures. The surface chemistry of the electrodes was studied using mainly diffuse reflectance Fourier transform infrared spectroscopy. The following aspects were studied: (i) the effect of temperature on the buildup of the surface films; (ii) the effect of additives (e.g., , crown ethers), (iii) the behavior when the passive layer is built in one solution followed by cycling in another; and (iv) the effect of cosolvent in MF solutions. The results obtained further prove that the electrochemical behavior of these systems is surface film controlled. An understanding of the surface chemistry of these electrodes enables judicious optimization of carbon‐solution systems for use in rechargeable Li batteries.
417 citations
TL;DR: In this article, the Curie-point pyrolysis-gas chromatography-mass spectrometry (Cu-Py-GC-MS) was used as an analytical tool for characterization of the resulting chars.
396 citations
TL;DR: The in vitro bioactivity of the new all-alkoxide gel-glasses is investigated and all compositions studied formed a hydroxy carbonate apatite (HCA) layer within 8 h in both test solutions.
Abstract: When soluble salts are used in the sol-gel processing of bioactive glasses, the resulting materials are not homogeneous. To produce homogeneous gel-glasses, a sol-gel method using all alkoxide precursors was developed. In this work the in vitro bioactivity of the new all-alkoxide gel-glasses is investigated. Three compositions in the system, CaO-P2O5-SiO2, were studied. Solid samples were soaked in Tris buffer and simulated body fluid (SBF), and the rate of formation of hydroxy carbonate apatite (HCA) on the surface of the glasses was measured by Fourier transform infrared spectroscopy. The solutions were analyzed before and after reaction by inductively coupled plasma. All compositions studied formed a hydroxy carbonate apatite (HCA) layer within 8 h in both test solutions. The HCA layer grew rapidly when SBF was used.
347 citations
TL;DR: Fourier-transform Raman spectrometry was shown to be a powerful tool for the investigation of primary cell-wall architecture at a molecular level, providing complementary information to that obtained by Fourier- transform infrared microspectroscopy.
Abstract: Infrared and Raman spectra of sequentially extracted primary cell walls and their pectic polymers were obtained from five angiosperm plants. Fourier-transform Raman spectrometry was shown to be a powerful tool for the investigation of primary cell-wall architecture at a molecular level, providing complementary information to that obtained by Fourier-transform infrared microspectroscopy. The use of an extraction procedure using imidazole instead of cyclohexane trans-1,2-N,N,N[prime],N[prime]-diaminotetraacetate allows the extension of the infrared spectral window for data interpretation from 1300 to 800 cm-1, to 2000 to 800 cm-1, and allows us to obtain Raman spectra from extracted cell-wall material. Wall constituents such as pectins, proteins, aromatic phenolics, cellulose, and hemicellulose have characteristic spectral features that can be used to identify and/or fingerprint these polymers without, in most cases, the need for any physical separation. The Gramineae (rice [Oryza sativa], polypogon [Polypogon fugax steud], and sweet corn [Zea mays]) are spectroscopically very different from the nongraminaceous monocotyledon (onion [Allium cepa]) and the dicotyledon (carrot [Daucus carota]); this reflects differences in chemical composition and cross-linking of the walls. The possibility of a taxonomic classification of plant cell walls based on infrared and Raman spectroscopies and the use of spectral fingerprinting for authentication and detection of adulteration of products rich in cell-wall materials are discussed.
342 citations
329 citations
TL;DR: Amorphous mixed valent manganese oxides, a new class of photocatalytic materials, were the most active catalysts studied at room temperature under visible light illumination.
Abstract: Amorphous manganese oxides, potassium oxalatomanganate complexes, and crystalline tunnel structure manganese oxides (hollandite, todorokite, pyrolusite) have been prepared and used as photocatalysts for the oxidation of 2-propanol to acetone. Amorphous mixed valent manganese oxides, a new class of photocatalytic materials, were the most active catalysts studied at room temperature under visible light illumination. High activities correlate with higher oxidation state manganese (Mn[sup 3+], Mn[sup 4+]) oxides, large surface oxygen concentrations, and the presence of hydroxyl groups on surfaces of these catalysts. BET (surface area analysis), XRD (X-ray diffraction), EDX (energy dispersive X-ray analysis), SEM (scanning electron microscopy), XPS (X-ray photoelectron spectroscopy), and FTIR (Fourier transform infrared) data support these correlations. A mechanism for these photooxidation flow reactions involving manganese oxide catalysts has been proposed. Photochemical and characterization data suggest that the design of active photocatalysts may rely on preparation of mixed valent amorphous oxides that release oxygen more readily than crystalline materials. Conversions as high as 8% and 100% selectivity to acetone have been realized with such systems. 45 refs., 9 figs., 1 tab.
229 citations
TL;DR: In this paper, Fourier transform infrared (FTIR) spectroscopy was used for the analysis of Safflower and cottonseed oils under various conditions, and their spectral changes were recorded and interpreted.
Abstract: Edible fats and oils in their neat form are ideal candidates for Fourier transform infrared (FTIR) analysis, in either the attenuated total reflectance or the transmission mode. FTIR spectroscopy provides a simple and rapid means of following complex changes that take place as lipids oxidize. Safflower and cottonseed oils were oxidized under various conditions, and their spectral changes were recorded and interpreted. The critical absorption bands associated with common oxidation end products were identified by relating them to those of spectroscopically representative reference compounds. The power and utilty of FTIR spectroscopy to follow oxidative changes was demonstrated through the use of “real-time oxidation plots.” A quantitative approach is proposed in which standards are used that are spectroscopically representative of oxidative end products and by which the oxidative state of an oil can be defined in terms of percent hydroperoxides, percent alcohols and total carbonyl content. By using either relative absorption as a basis or calibrating on representative standards, FTIR analysis provides a rapid means of evaluating the oxidative state of an oil or of monitoring changes in oils undergoing thermal stress.
229 citations
TL;DR: Information on the bonding of organic ligands to hydrous metal oxide surfaces, necessary to gain insight into the mechanisms of surface reactivity, was extracted using attenuated total reflection-Fourier transform infrared spectroscopy.
Abstract: Information on the bonding of organic ligands to hydrous metal oxide surfaces, necessary to gain insight into the mechanisms of surface reactivity, was extracted using attenuated total reflection-Fourier transform infrared spectroscopy. Various ligands were investigated in-situ on the surface of δ-Al 2 O 3 in water. Keeping the study of structure with respect to surface reactivity in the foreground, we report here specifically on the model ligand salicylate, which we also examined on the surfaces of other oxides, including corundum, hematite, lepidocrocite, and goethite. Because the direct ligand-metal bond vibrations absorb in the same region as the metal-oxygen vibrations in the bulk oxide, evidence of bonding was obtained by observing changes in the spectrum of the ligand itself
198 citations
TL;DR: In this article, the growth of thin carbon nitride films on Si(100) substrates at temperatures in the range of 100-700°C using electron-beam evaporation of graphite assisted with electron cyclotron resonance (ECR) plasma generated nitrogen species.
Abstract: We report the growth of thin carbon nitride films on Si(100) substrates at temperatures in the range of 100–700 °C using electron‐beam evaporation of graphite assisted with electron cyclotron resonance (ECR) plasma generated nitrogen species. The effect of the substrate temperature, and the nitrogen flow on the composition ratio C/N, and the C—N bonding were investigated using Fourier transform infrared spectroscopy (FTIR), x‐ray photoelectron spectroscopy (XPS), Rutherford backscattering spectroscopy (RBS), and Raman spectroscopy. The FTIR spectra show that the films produced exhibit a very high visible to infrared transmittance (0.85–0.95). These spectra were dominated by amine group (NH2) with the presence of C‐N stretching modes. From both RBS and XPS, the nitrogen concentration in the film was calculated and was found in the range of 24%–48%, depending on the nitrogen partial pressure in the ECR source. Raman spectrum of the high nitrogen content thin film shows a well resolved peak at 1275 cm−1 sugg...
191 citations
TL;DR: A Fourier transform infrared spectroscopic method has been developed to analyze protein secondary structure by employing the amide III spectral region (1350-1200 cm-1).
Abstract: A Fourier transform infrared spectroscopic method has been developed to analyze protein secondary structure by employing the amide III spectral region (1350-1200 cm-1) Benefits of using the amide III region have been shown to be substantial The interference from the water vibration (~ 1640 cm-1) in the amide I region can be avoided when one is using the amide III band; furthermore, the amide III region also presents a more characterized spectral feature which provides easily resolved and better defined bands for quantitative analysis Estimates of secondary structure are accomplished with the use of Fourier self-deconvolution, second derivatization, and curve-fitting on original protein spectra The secondary structure frequency windows (α-helix, 1328-1289 cm-1; unordered, 1288-1256 cm-1; and β-sheets, 1255-1224 cm-1) have been obtained, and estimates of secondary structural contents are consistent with X-ray crystallography data for model proteins and parallel results obtained with the use of the amide I region We have further applied the analysis to the structural change of calsequestrin upon Ca2+ binding Treatment of calsequestrin with 1 mM Ca2+ results in the formation of crystalline aggregates accompanied by a 10% increase in α-helical structure, which is consistent with previous results obtained by Raman spectroscopy Thus the amide III region of protein IR spectra appears to be a valuable tool in estimating individual protein secondary structural contents
TL;DR: In this paper, a new interlayer dielectric film using fluorine-doped silicon oxide (SiOF) for multilevel interconnection of very large scale integration (VLSI) has been fabricated.
Abstract: A new interlayer dielectric film using fluorine-doped silicon oxide (SiOF) for multilevel interconnection of very large scale integration (VLSI) has been fabricated The film is deposited by a simple technique, which is hexafluoroethane ( C2F6) addition to conventional tetraethoxysilane (TEOS)-based plasma-enhanced chemical vapor deposition (PE-CVD) Si–F bond formation in the film is detected by chemical bonding structural studies using Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS) Low dielectric constants caused by Si–F bond formation and good gap-filling ability due to in situ etching by C2F6 plasma are obtained Therefore, SiOF film has very high applicability as an interlayer dielectric film for advanced VLSI devices
TL;DR: In this article, a Fourier transform infrared (FTIR) transmission spectroscopy method for peroxide value determination of vegetable oils is described, which takes an average of three minutes per sample.
Abstract: A rapid method for the quantitative determination of peroxide value (PV) of vegetable oils by Fourier transform infrared (FTIR) transmission spectroscopy is described. Calibration standards were prepared by the addition oft-butyl hydroperoxide to a series of vegetable oils, along with random amounts of oleic acid and water. Additional standards were derived through the addition of mono- and diglyceride spectral contributions, as well as zero PV spectra obtained from deuterated oils. A partial least squares (PLS) calibration model for the prediction of PV was developed based on the spectral range 3750–3150 cm−1. Validation of the method was carried out by comparing the PV of a series of vegetable oils predicted by the PLS model to the values obtained by the American Oil Chemists Society iodometric method. The reproducibility of the FTIR method [coefficient of variation (CV)=5%)] was found to be better than that of the chemical method (CV =9%), although its accuracy was limited by the reproducibility of the chemical method. The method, as structured, makes use of a 1-mm CaF2 flow cell to allow rapid sample handling by aspiration. The spectrometer was preprogrammed in Visual Basic to guide the operator in performing the analysis so that no knowledge of FTIR spectroscopy is required to implement the method. The method would be suitable for PV determinations in the edible oil industry and takes an average of three minutes per sample.
TL;DR: A series of four polycarbonates derived from the ethyl, butyl, hexyl, and octyl esters of desaminotyrosyl-tyrosine was prepared by condensation polymerization, and their chemical structure was confirmed by elemental analysis, nuclear magnetic resonance, and Fourier transform infrared spectroscopy.
Abstract: A series of four polycarbonates derived from the ethyl, butyl, hexyl, and octyl esters of desaminotyrosyl-tyrosine was prepared by condensation polymerization. The resulting polymers had weight average molecular weights ranging from 120,000-450,000, and their chemical structure was confirmed by elemental analysis, nuclear magnetic resonance, and Fourier transform infrared spectroscopy. The polycarbonates were evaluated as degradable biomaterials. Their surface properties were determined by electron spectroscopy for chemical analysis, attenuated total reflectance-Fourier transformed infrared spectroscopy, and contact angle measurement. The degree of surface hydrophobicity was related to the length of the alkyl ester pendent chain. The tensile properties were dependent on the chemical structure of the polymers: For thin, solvent cast film specimens, the tensile modulus varied from 1.2-1.6 GPa, and the strength at break from 60-220 MPa. The degradation of polymeric films was followed in vitro by measuring changes in mechanical strength for up to 40 weeks, and the decrease in molecular weight and changes in surface chemistry for up to 80 weeks. The length of the pendent chain affected the degradation behavior and strength retention; the polymers with short pendent chains were more readily hydrolyzable. For sterilization, ethylene oxide treatment was less destructive, as judged by molecular weight retention, than gamma-irradiation. Spin-cast films of all tested polycarbonates were not cytotoxic toward cultured rat lung fibroblasts. The cell response was influenced by the chemical structure of the polymer. The least hydrophobic polycarbonate (having a short ethyl ester pendent chain) was a more stimulating substrate for cell growth than the more hydrophobic polymers (carrying longer alkyl ester pendent chains).
TL;DR: In this paper, Fourier transform infrared (FTIR) spectroscopy and small-angle X-ray scattering (SAXS) techniques were used to study the interaction between asphaltenes and two alkylbenzene-derived amphiphiles, palkylphenol and p-alkylbenzenesulfonic acid.
Abstract: In the preceding paper in this issue, the influence of the chemical structure of a series of alkylbenzene-derived amphiphiles on the stabilization of asphaltenes was described. In this paper, we present the results of using Fourier transform infrared (FTIR) spectroscopy and small-angle X-ray scattering (SAXS) techniques to study the interaction between asphaltenes and two alkylbenzene-derived amphiphiles, p-alkylphenol and p-alkylbenzenesulfonic acid. FTIR spectroscopy was used to characterize and quantify the acid-base interactions between asphaltenes and amphiphiles. It was found that asphaltenes could hydrogen-bond to p-dodecylphenol amphiphiles. The hydrogen-bonding capacity of asphaltenes was estimated to be 1.6-2.0 mmol/g of asphaltene. On the other hand, the FTIR spectroscopic study indicated that asphaltenes had a complicated acid-base interaction with p-dodecylbenzenesulfonic acid (DBSA) amphiphiles with a stoichiometry of about 1.8 mmol of DBSA/g of asphaltene. The UV/vis spectroscopic study suggested that asphaltenes and DBSA could associate into large electronic conjugated complexes. Physical evidence of the association between asphaltenes and amphiphiles was obtained by SAXS measurements. 27 refs., 10 figs.
TL;DR: In this article, Fourier transform infrared (FTIR) spectroscopy was used in conjunction with principal component analysis (PCA) and discriminant analysis to investigate the potential of the technique for determining the authenticity of vegetable oils.
Abstract: Fourier transform infrared (FTIR) spectroscopy was used in conjunction with principal component analysis (PCA) and discriminant analysis to investigate the potential of the technique for determining the authenticity of vegetable oils. PCA applied to spectra from a range of seed oils revealed clustering according to plant species. When extra virgin and refined olive oils were subjected to discriminant analysis, 93% of samples in a calibration set and 100% of samples in an independent validation set were correctly classified, despite these two types of oil being chemically and spectroscopically very similar. The method, therefore, has potential as a rapid method for the determination of product authenticity
TL;DR: In this article, the electrostatic adsorption of poly-L-lysine molecules onto a vapor-deposited gold film modified with a carboxylic acid-terminated alkanethiol monolayer is monitored with the spectroscopic techniques of polarization-modulation Fourier transform infrared (PM-FTIR) spectroscopy and surface plasmon resonance (SPR).
Abstract: The electrostatic adsorption of poly-L-lysine molecules onto a vapor-deposited gold film modified with a carboxylic acid-terminated alkanethiol monolayer is monitored with the spectroscopic techniques of polarization-modulation Fourier transform infrared (PM-FTIR) spectroscopy and surface plasmon resonance (SPR). The PM-ITIR spectrum of a monolayer of poly-L-lysine (PL) adsorbed onto a self-assembled monolayer of 11-mercaptoundecanoic acid (MUA) indicates that the lysine residues and the MUA carboxylic acid moieties form ammonium-carboxylate ion pairs which electrostatically bind the polypeptide to the surface. The PL molecules can be desorbed from the surface by rinsing with a buffer solution at a pH that destroys the ion pairing (pH 12). Measurements of the shift in the SPR angle upon adsorption were used to determine the thicknesses of the adsorbed monolayers; the MUA and PL monolayers were found to be 17.0 and 10.5 A thick, respectively. These thickness results suggest that the poly-L-lysine monolayer adsorbs onto the packed MUA surface in an extended conformation with the PL backbone lying parallel to the surface. Subsequent exposure ofthe PL monolayer to a solution ofiron phthalocyanine tetracarboxylic acid (FePc) resulted in the adsorption of a third layer onto the surface. The ability of the adsorbed PL molecules to interact with FePc indicates the presence of free lysine residues available for interaction with molecules other than the MUA monolayer.
TL;DR: In this paper, phase transitions in the α-, β-, γ-, and ϵ-polymorphs of 2,4,6,8,10,12-hexanitrohexaazaisowurtzitane (HNIW) have been studied as a function of temperature.
Abstract: Phase transitions in the α-, β-, γ-, and ϵ-polymorphs of 2,4,6,8,10,12-hexanitrohexaazaisowurtzitane (HNIW) have been studied as a function of temperature. Described are the results of high temperature equilibrium solvation studies coupled with Fourier transform infrared spectroscopy (FTIR) for the identification of polymorphic conversion. These results are augmented by data in Part II from differential scanning calorimetry (DSC), differential thermal analysis/thermogravimetric analysis (DTA/TGA), and optical hot stage microscopy(6). The thermodynamic stability order of ϵ > γ > α-hydrate > β is shown, with the epsilon polymorph the most thermodynamically stable phase of HNTW at room temperature. The existence of multiple α-hydrate phases is shown to complicate the determination of the equilibrium P-T phase diagram of HNIW.
TL;DR: The surface oxidation of galena subject to various conditioning environments has been investigated by dissolution kinetics studies, Fourier transform infrared (FTIR), and X-ray photoelectron spectroscopies (XPS).
TL;DR: Faix et al. as mentioned in this paper evaluated hydroxyl groups in Lignins using -9€-, 9€, 9 FTIR and Wet Chemical Methods and found that hydroxy groups in lignins are more stable than other groups.
Abstract: Determination of Hydroxyl Groups in Lignins Evaluation of -9€-, 9 FTIR and Wet Chemical Methods By Oskar Faix, Dimitris S. Argyropoulos, Danielle Robert and Vincent Neirinck Bundesforschungsanstalt für Forstund Holz Wirtschaft, Institut für Holzchemie und chemische Technologie des Holzes, Hamburg, Federal Republic of Germany Pulp and Paper Research Centre, McGill University, Montreal, Canada C.E.N.G., DRFMC, Service d'Etudes des Systemes Moleculaires, Grenoble, France
Patent•
IBM1
TL;DR: In this paper, a method and apparatus for monitoring and controlling reactant vapors prior to chemical vapor deposition (CVD) is presented, without sampling, at full concentration without sampling as they are transported to a CVD reactor.
Abstract: A method and apparatus for monitoring and controlling reactant vapors prior to chemical vapor deposition (CVD). The reactant vapors are monitored at full concentration without sampling as they are transported to a CVD reactor. Contaminants detected cause a process controller to switch the transport path to direct reactant vapors to a system pump.
TL;DR: A Fourier transform infrared spectrometer has been interfaced with a surface balance and a new external reflection infrared sampling accessory, which permits the acquisition of spectra from protein monolayers in situ at the air/water interface to reduce interference from water vapor rotation-vibration bands in the amide I and amide II regions of protein spectra.
TL;DR: In this article, a method for determining the loadings of organic and inorganic functional groups in size segregated ambient aerosol has been developed and demonstrated, using a Hering Low Pressure Impactor (LPI), equipped with ZnSe impaction surfaces, to sample the aerosol.
Abstract: A method for determining the loadings of organic and inorganic functional groups in size segregated ambient aerosol has been developed and demonstrated. The method uses a Hering Low Pressure Impactor (LPI), equipped with ZnSe impaction surfaces, to sample the aerosol. The aerosol samples are analyzed directly, without extraction, using transmission infrared spectroscopy. The resulting spectra of aerosol size fractions are used to determine loadings of sulfate ion, nitrate ion, aliphatic carbon, carbonyl and organonitrate groups, using calibration factors developed in field and model compound studies. This paper describes, in detail, the data interpretation and calibration methods used to obtain these functional group loadings from the infrared spectra. The functional group loadings, particularly the size distributions of organic compound classes, provide new insights into the composition of atmospheric aerosol.
TL;DR: In this article, the influence of culture conditions on FTIR spectra and the discrimination of Lactobacillus species found in breweries was investigated. But the results were limited.
Abstract: Fourier Transform infrared (FTIR) spectroscopy can be used to identify microorganisms. This study describes the influence of culture conditions on FTIR spectra and the discrimination of Lactobacillus species found in breweries. Fifty three Lactobacillus strains were analysed by FTIR spectroscopy and identification at the species level was correct for 94% of the strains, and at the strain level for 91% of the strains.
TL;DR: In this paper, in-situ Fourier transform IR spectroscopy has been employed to study the adsorption of acetate on Pt(100), Pt(110) and Pt(111) electrodes.
TL;DR: In this paper, Fourier transform infra-red (FTir) spectroscopy and potentiometric techniques were used to characterize the nature of such interactions, in aqueous solutions and in films.
TL;DR: In this paper, Sb doped and undoped SnO2 thin solid coatings were prepared by the dip-coating technique via the sol-gel route, which was achieved through the addition of SbCl3 in the concentration range 1-10 mol%.
Abstract: Sb doped and undoped SnO2 thin solid coatings were prepared by the dip-coating technique via the sol-gel route. Aqueous gels of undoped compound were made by using a SnCl4 precursor and doping was achieved through the addition of SbCl3 in the concentration range 1–10 mol%. Fourier transform infrared (FTIR), ATR and near normal reflectance spectroscopic techniques were utilized to determine the vibrational spectra of aqueous gels, xerogels and oxides of Sb doped and undoped compounds. Analysis of the corresponding FTIR spectra revealed the existence of Sb-O modes at 770 cm−1. The drying of both types of gel was accompanied by the formation of hydrogen bonds of medium strength wit the OH-O length about 2.7–2.8 A. Some properties of pure and Sb doped oxide powders formed in the temperature range ≤1000°C were measured by the thermogravimetry, X-ray diffraction and FTIR spectroscopic techniques. The doping brought about a broadening of the X-ray diffraction peaks. The reflectivity of the samples increased in the spectral range 4000-600 cm−1 up to 60%, due to the formation of plasma modes. Thin solids films were made by the dip-coating method. The efficiency of the dip-coating process was 0.02–0.1 μm per dipping, depending on the viscosity of the gel. The electrical resistivity of the doped SnO2 coatings was about 1.2 × 10−2 ω cm and thus comparable to the electrical resistivity of the alkoxide derived Sb doped SnO2. Doping decreased visible transmittance ∼5% but infrared reflectance increased up to 40%, depending on the film thickness.
TL;DR: In this article, a nanosecond time-resolved infrared spectroscopic system based on a dispersive scanning spectrometer has been constructed, which is an advanced version of a similar system reported in a previous paper; the time resolution has been improved from 1 μs to 50 ns and the sensitivity from 10-4 in intensity changes to 10-6.
Abstract: A nanosecond time-resolved infrared spectroscopic system based on a dispersive scanning spectrometer has been constructed. This is an advanced version of a similar system reported in a previous paper; the time resolution has been improved from 1 μs to 50 ns and the sensitivity from 10-4 in intensity changes to 10-6. These have been achieved by the use of a high-temperature ceramic infrared light source, a photovoltaic MCT detector, and a low-noise, wide-band preamplifier developed specifically for the present purpose. Time-resolved infrared spectra of a few samples of photochemical and photobiological interests are presented to show the capability of the system. The origin of the thermal artifacts, which have been found to hamper the time-resolved infrared measurements seriously, is shown to be due to the transient reflectance change induced by a small temperature jump. The future prospect of time-resolved infrared spectroscopy is discussed with reference to other methods including infrared laser spectroscopy and Fourier transform infrared spectroscopy.
TL;DR: In this article, the change in the spectra of stretching vibrations of the decoupled OD oscillator in 3.6 mole % HOD in H2O was studied by Fourier transform infrared spectroscopy.
Abstract: Metastable liquid water, obtained by heating its hyperquenched glassy state above its glass→liquid transition temperature, crystallizes to cubic ice. Kinetics of this crystallization has been studied by Fourier transform infrared spectroscopy by determining the change in the spectra of stretching vibrations of the decoupled OD oscillator in 3.6 mole % HOD in H2O. The crystallization kinetics follows the equation x=[1−exp(−ktn)] and is diffusion controlled. Annealing at a temperature below its glass→liquid transition temperature alters this kinetics as the grain–growth process begins to control the early stages of crystallization.