bluuebunny/crossref_metadata_2025 huggingface dataset:
Determination of Carbon Content in Steel Using Laser-Induced Breakdown Spectroscopy
Authors: Aguilera J. A. , Aragón C. , Campos J.
Published: June 2005

Laser-induced breakdown spectroscopy has been used to determine carbon content in steel. The plasma was formed by focusing a Nd:YAG laser on the sample surface. With the use of time-resolved spectroscopy and generation of the plasma in nitrogen atmosphere, a precision of 1.6% and a detection limit of 65 ppm have been obtained. These values are similar to those of other accurate conventional techniques. Matrix effects for the studied steels are reduced to a small slope difference between the calibration curves for stainless and nonstainless steels.
A Device for Surface-Scanning Micro-Raman Spectroscopy
Authors: Lankers M. , Göttges D. , Materny A. , Schaschek K. , Kiefer W.
Published: June 2005

A simple but very efficient device for micro-Raman spectroscopy of highly absorbing solid samples is described. The device allows rapid scanning of the focused laser beam on the surface of a solid sample, which avoids heating of the sample. By means of a pair of computer-controlled piezo-translators, which are fixed to the microscope objective, the laser beam can be scanned in a great variety of traces, the scattered light of which is collected and optically transformed into a very small spot at the entrance slit of the spectrometer. The system is tested on highly absorbing (partially) polymerized diacetylene single crystals at low temperatures.
Application of DRIFT Spectroscopy for Comparison of Dye Mixtures Extracted from Small Textile Samples
Authors: Kokot S. , Carswell S. , Massart D. L.
Published: June 2005

DRIFT spectra were collected from dye mixtures extracted from small yarn samples taken from several areas of a worn test garment. Raw and pretreated data matrices were interpreted with the use of chemometrics (PCA, SIMCA, fuzzy clustering). This approach showed that spectra cluster and match according to their sampling area on the test textile. The DRIFT results provide detailed information that is not available from the application of the usual techniques (e.g., TLC) with such samples and therefore should be of use in forensics or similar work where comparisons of unknown, small dye mixtures are required.
Dynamic Effects in CO Adsorption on Ru/ZSM-5. Part I: Oxidative Disruption of Ru
Authors: Shen J. Y. , Sayari A. , Kaliaguine S.
Published: June 2005

In situ diffuse reflectance infrared spectroscopy of CO adsorption on reduced Ru/ZSM-5 reveals that, under appropriate conditions, in addition to the linearly adsorbed CO on metallic Ru particles (at 2045 ± 10 cm−1), two multicarbonyls involving oxidized Ru can be generated. These multicarbonyl species are characterized by IR doublets at 2080 and 2138 cm−1 and at 2086 and 2150 cm−1, respectively. Direct evidence for the consumption of both types of the ZSM-5 surface hydroxyl groups (silanol and Brønsted) during the oxidative adsorption of CO has been obtained. Each of these two OH types is believed to be associated with one of the multicarbonyl species.
Mueller Matrix Approach to Fluorescence Spectroscopy. Part I: Mueller Matrix Expressions for Fluorescent Samples and Their Application to Problems of Circularly Polarized Emission Spectroscopy
Authors: Shindo Yohji , Oda Yasunori
Published: June 2005

Mueller matrixes are presented for optically inactive and fluorescent samples with and without photo-selection, and for optically active and fluorescent ones with and without photo-selection, in order to analyze phenomena observed in fluorescence polarization. Absorption-fluorescence transformation matrices are introduced in the derivation of formula to take account of the process occurring during the interval between excitation and emission. Mueller matrix expressions derived are used for investigating the problems of circularly polarized emission (CPE) and linearly polarized emission (LPE) measurements. It is found that they are useful not only in analyzing the effects of experimental systems on fluorescence polarization spectroscopy but also in the design, analysis, and evaluation of CPE and LPE spectrometers.
Structural Studies of Crystalline Linear Polyethylenes as Revealed by Factor Analysis of Their Raman Spectra
Authors: Shen Chengbo , Peacock Andrew J. , Alamo Rufina G. , Vickers Thomas J. , Mandelkern Leo , Mann Charles K.
Published: June 2005

Seven samples of linear polyethylene which show quite different levels of crystallinity were prepared and Raman spectra of them were measured. The spectra of these samples show a series of narrow bands superimposed on very broad bands. This pattern is recognized to be the consequence of partial crystallization to give material consisting of lamellar crystallites connected with amorphous material. The narrow peaks are identical to those of crystalline polyethylene. The broad bands are identical to those of a polyethylene melt. Factor analysis of the spectra shows the existence of a third component which has a spectrum quite similar to that of the crystalline region. An estimation of the spectrum of this component is presented. It is based upon combinations of abstract factors and upon subtraction of the contributions by the two prominent components from mixture spectra. The third spectrum, attributed to an interracial region surrounding the crystallites in which partial order exists, closely resembles that of crystalline polyethylene, but with somewhat broader peaks that are shifted in position.
High-Fidelity Raman Imaging Spectrometry: A Rapid Method Using an Acousto-Optic Tunable Filter
Authors: Treado Patrick J. , Levin Ira W. , Lewis E. Neil
Published: June 2005

In this communication, we describe a technique for obtaining high-fidelity Raman images and Raman spectra. The instrumentation provides the ability to rapidly collect large-format images with the number of image pixels limited only by the number of detector elements in the silicon charge-coupled device (CCD). Wavelength selection is achieved with an acousto-optic tunable filter (AOTF), which maintains image fidelity while providing spectral selectivity. Under computer control the AOTF is capable of µs tuning speeds within the operating range of the filter (400–1900 nm). The AOTF is integrated with the CCD and holographic Raman filters to comprise an entirely solid-state Raman imager containing no moving parts. In operation, the AOTF is placed in front of the CCD and tuned over the desired spectral interval. The two-dimensional CCD detector is employed as a true imaging camera, providing a full multichannel advantage over competitive Raman imaging techniques. Images and spectra are presented of a mixture of dipalmitoylphosphatidylcholine (DPPC) and L-asparagine, which serves as a model system for the study of both lipid/peptide and lipid/protein interactions in intact biological materials. The Raman images are collected in only several seconds and indicate the efficacy of this rapid technique for discriminating between multiple components in complex matrices. Additionally, high-quality Raman spectra of the spatially resolved microscopic regions are easily obtained.
Description and Characterization of a Linear-Flow Outer Gas Flow Torch for Inductively Coupled Plasma Emission Spectroscopy
Authors: Rayson Gary D. , Shen Daniel Yang
Published: June 2005

An inductively coupled plasma torch has been developed which utilizes linear coolant gas flows and is operated at reduced applied power levels and argon gas consumption rates. The linear flow torch (LiFT) is constructed by the addition of a machined insert between the outer and intermediate tubing of a conventional tangential flow torch (TaFT). This LiFT configuration has been demonstrated to be capable of providing improved detection limits, in comparison to a TaFT, at conditions of lower power and gas flow. Under those conditions the LiFT was also demonstrated to produce less severe interferences to analyte emission in the presence of an easily ionizable element.
Dynamic Effects in CO Adsorption on Ru/ZSM-5. Part II: Thermal Stability and Reactivity of CO Adsorbed Species
Authors: Shen J. Y. , Sayari A. , Kaliaguine S.
Published: June 2005

The stability and reactivity of CO species adsorbed on Ru/ZSM-5 have been studied by in situ diffuse reflectance infrared spectroscopy (DRIFT). Three species were detected: a linearly adsorbed CO (2045 ± 10 cm−1) on metallic Ru and two multicarbonyl species (2138-2080 cm−1 and 2150-2086 cm−1) on oxidized Ru. The most strongly held species was the linearly adsorbed CO. Among the two multicarbonyl species, the one showing a doublet at 2150 and 2086 cm−1 was more stable than the other. Because it is believed that the formation of the 2150-2086 cm−1 and the 2138-2080 cm−1 species involved silanol and Brønsted OH groups, respectively, it is inferred that the species with a low-frequency doublet (2138-2080) is predominantly located within the pore network of the HZSM-5 zeolite, while the other multicarbonyl species is mainly sited on the external surface of the zeolite. The latter species was found to be more stable than the other multicarbonyl species.
New Method for Preparation of Samples for Measurement of Electronic Absorption Spectra of Difficult Soluble Inorganic and Metallorganic Compounds
Authors: Mikhailov O. V.
Published: June 2005

A new method has been developed for the preparation of test samples for the registration of standard electronic absorption spectra of insoluble inorganic and metallorganic compounds in which—unlike traditional spectroscopic methods—the analyzed substances are synthesized by a series of specific chemical processes in thin gelatin layers of various silver halogenide photographic materials. Some advantages of these test samples, in comparison with standard solutions of analyzed compounds and mechanical mixtures of ones with various fillers, have been demonstrated. In addition, examples of the preparation of test samples of some insoluble substances [including iron(III)-potassium ferrocyanide (KFe[Fe(CN)6]), chromium dioxide (CrO2), copper(II)-dithiooxamide chelate (CuC4N4S4H6), etc.] and the electronic absorption spectra of some samples have been given.
Measurements and Theory of Signal-to-Noise Ratio of FT-IR Emission Spectrometry Applied to High-Pressure Solid Propellant Combustion
Authors: Huang I. T. , Thynell S. T. , Kuo K. K.
Published: June 2005

Solid propellant combustion studies at high pressures (500–50,000 psi) must be conducted with a high spatial resolution in order to resolve the species concentration and flame temperature profiles. Such studies are often performed in specifically designed experimental facilities, including chimney-type strand burners. To successfully carry out FT-IR emission spectrometry of products from the combustion of small propellant strands, one is required to perform a critical assessment of the achievable signal-to-noise ratio (SNR). In this work, an analytical expression for the SNR of FT-IR emission spectrometry limited to detector noise has been derived. The expression is specifically applied for the ν3 fundamental band of CO2 and in the optically thick limit verified by experiments. The results from the application of the theory show that a spatial resolution on the order of 200 μm should yield SNRs of 100 or larger at the center of the considered band for the anticipated temperatures of high-pressure solid propellant combustion. Measurements of emission spectra of combustion products of a homogeneous solid propellant, NO-SOL-363, have also been performed at one atmosphere total pressure to show that an 800-jun spatial resolution may be sufficient to deduce species concentration and temperature profiles.
Side-View Type of Waveguide Flow Cells for Fluorimetry as a Detector for Flow Injection Analysis of Lead
Authors: Fujiwara Kitao , Seiji Ito , Kojyo Ri-E , Tsubota Hiroyuki , Carter Randolph L.
Published: June 2005

Several types of cells made of Pyrex® ( nD20 = 1.474) capillaries were constructed for fluorimetry from the standpoint of waveguiding of the excitation source. Fluorescence intensity detected from a vortex cell is virtually linearly dependent on the refractive index of the solvent containing the fluorophore. This type of cell is applied as the fluorimctric detector for the flow injection analysis of the lead(II) ion. The lead ion was incorporated into a macrocyclic ligand, cryptand 2.2.2, and the resulting compound was ion-paired with eosine (fluorescent dye). This complex ([Pb(cryptand 2.2.2)]eosine) was extracted into chlorobenzene ( nD20 = 1.5248) and was introduced into the above vortex cell. An Ar+ laser operated at 514.5 nm was used as the light source, and the fluorescence of eosine at 600 nm was detected. Two ng/mL of Pb(II) ion was obtained as the detection limit.
A Molecular Fluorescence Spectrometer That Corrects for the Effects of Quenching
Authors: Bowman L. E. , Crouch S. R.
Published: June 2005

A fluorescence spectrometer has been constructed that simultaneously determines fluorescence intensity and excited-state lifetime. The ratio of intensity to lifetime is used to correct for the reduction in fluorescence intensity caused by collisional quenching. A frequency-domain technique is used to determine the excited-state lifetime in real-time. Computer-driven data acquisition provides instantaneous readout of the fluorescence intensity, the excited-state lifetime, and the ratio of these quantities. Correction for quenching by oxygen is demonstrated.
A Demonstration of Truly Remote In-Line Near-Infrared Process Analysis
Authors: Mackison R. , Brinkworth S. J. , Belchamber R. M. , Aries R. E. , Cutler D. J. , Deeley C. , Mould H. M.
Published: June 2005

A system for truly remote near-infrared (NIR) analysis of multiple process streams is described. The system utilizes a standard laboratory Fourier transform (FT) NIR spectrophotometer, housed remotely from the plant in a safe area. NIR radiation is transmitted between the spectrophotometer and the process stream by a pair of multimode silica optical fibers and an optical multiplexer. The qualitative and quantitative performance of the system, over the 1- to 2- μm region, is demonstrated with total optical fiber lengths of 2 km. The results of an analysis of a set of aliphatic alcohol mixtures, using the process analysis system, are compared with those obtained with a normal laboratory instrument.
Effect of Overlapping Bands on Intensities in ATR FT-IR Spectra
Authors: Huang J. B. , Urban M. W.
Published: June 2005

In this study, several spectra were simulated, and the effect of spectral resolution and intensity is compared for ATR and transmission measurements. The analysis of ATR spectra shows that the intensity differences become more pronounced with the increasing band intensities and decreasing separation of the bands. The intensity ratio differences in ATR spectra are due to the superposition of the asymmetric dispersion bands of the refractive index spectrum. The difference between the spectral features in an overlapping region in ATR and transmission measurements is illustrated, and it is shown that the optical dispersion effect can be effectively eliminated by converting an ATR spectrum into its absorbance counterpart with the use of the Kramers-Kronig transform.
Chemiluminescence from Sulfur Compounds in Novel Flame and Discharge Systems: Proof of Sulfur Dioxide as the Emitter in the New Sulfur Chemiluminescence Detector
Authors: Martin Harold R. , Glinski Robert J.
Published: June 2005

Gases from a hydrogen-rich, sulfur-dioxide-containing, hydrogen/oxygen flame were drawn into a reduced-pressure reaction vessel and reacted with ozone. Spectroscopic analysis of the low-pressure chemiluminescence showed that electronically excited sulfur dioxide is the principal emitter exploited in the new sulfur chemiluminescence detector (SCD). Sulfur dioxide phosphorescence was found to contribute significantly to the total emission, suggesting that the technique could be enhanced by detecting more of the phosphorescence at higher total pressures. A calibration plot of signal vs. sulfur dioxide concentration was found to have a slight positive curvature. Interferences from NO2* and OH* were spectroscopically characterized; it is suggested that these could be minimized in the SCD by judicious choice of the wavelength discrimination filter. Utilization of a microwave discharge was similarly efficient at producing the chemiluminescence.
Post-Prandial Blood Glucose Determination by Quantitative Mid-Infrared Spectroscopy
Authors: Ward Kenneth J. , Haaland David M. , Robinson M. Ries , Eaton R. Philip
Published: June 2005

The multivariate calibration method of partial least-squares (PLS) was applied to the mid-infrared spectra of whole blood for quantitatively determining blood glucose concentrations. Separate calibration models were developed on the basis of spectra of whole blood obtained from six diabetic subjects from either in vitro glucose-supplemented blood or blood obtained from the same subjects in the post-prandial state during meal tolerance tests. The cross-validated PLS calibrations yielded average errors in glucose concentration of 11 and 13 mg/dL, respectively. It is desirable to use the calibration models based on the in vitro glucose-supplemented blood for determining glucose concentrations in unknown blood samples. However, when these multivariate calibration models based upon in vitro blood spectra were applied to the spectra of the postprandial blood samples, a subject-dependent concentration bias was observed. The source of this bias was not identified, but when the glucose determinations were corrected for the bias, average concentration errors were found to be 14 mg/dL. Changes in spectrometer design or calibrations based on large numbers of subjects are expected to eliminate the presence of this bias. If these measures do not succeed in eliminating the bias, then methods are demonstrated that significantly reduce the bias while retaining the sensitive outlier detection capabilities of the PLS methods. These latter methods require that the infrared spectrum and reference glucose levels be obtained from a single blood sample from each subject.
Differential Vaporization during Laser Ablation/Deposition of Bi-Sr-Ca-Cu-O Superconducting Materials
Authors: Chan Wing-Tat , Mao X. L. , Russo Richard E.
Published: June 2005

Nanosecond and picosecond pulsed laser ablated materials from Bi-Sr-Ca-Cu-O superconducting targets are monitored by inductively coupled plasma-atomic emission spectrometry with a photodiode array detector. Differential vaporization was observed; elements of the lower-melting-point oxides (Bi2O3, and CuO) are enriched in the vapor phase, indicating a thermal vaporization mechanism. Melted droplets observed with SEM and enriched Ca and Sr content in the ablation crater measured with EDX support the hypothesis. A steady-state mass ablation composition after prolonged laser sampling is also observed; the ratios of intensity for Bi, Ca, and Sr to Cu are constant for power density 0.1 to 3.0 GW/cm2.
Optimization of a Boxcar Integrator/Averager System for Excited-State Lifetime Measurements
Authors: Novo João B. Marques , Pessine Francisco B. T.
Published: June 2005

The instrumental distortions due to adjustable parameters of the SR250 boxcar integrator/averager system and a pulsed-laser luminescence spectrometer on the excited-state lifetime decay waveforms were investigated. A theoretical model which takes into account the exponential moving average for this instrument and also RC distortion on the time-dependent luminescence signal is presented. An analytical expression relating the sample's excited-state lifetime and the adjustable instrumental parameters such as laser repetition rate, gate scan time, gate width, scan width, number of samples averaged, and RC time constants from cables, termination, and other coupled instruments was obtained. Computer simulation using this expression was performed, and the good agreement found between the simulated and the experimental decay curves showed that the proposed mathematical equation can be applied to the optimization of instrumental parameters as well as in least-squares data reduction methods for luminescence kinetics measurements.
Determination of Sugars and Organic Acids in Fruit Juices by FT Mid-IR Investigation of Dry Extract
Authors: Dupuy N. , Meurens M. , Sombret B. , Legrand P. , Huvenne J. P.
Published: June 2005

In an extension of the approach adopted by Meurens et al. for dispersive NIR spectroscopy, the principle of using dry extracts has been applied to FT-IR spectroscopy, to make use of three advantages: the rapidity of Fourier transform spectroscopy, the solvent elimination, and the better peak resolution in the mid-IR region. However, sampling appears more difficult in mid-IR than in NIR spectroscopy. The feasibility of quantitative analysis has, in a first step, been tested on synthetic samples before application to natural fruit juices. The performance of our dry extract method is reported in terms of spectroscopy as well as of multicomponent quantitative analysis of sugars and organic acids in fruit juices.
Spectroscopy with Nonimaging Optics: Application to the Infrared Spectroscopy of Langmuir Monolayers
Authors: Buontempo Joseph T. , Rice Stuart A.
Published: June 2005

We discuss the principles of nonimaging optics and demonstrate how nonimaging concentrators can be used to maximize the collection of low-intensity infrared light. Specifically, we show that infrared reflection-absorption spectra can be obtained from a Langmuir monolayer of heneicosanol with a reasonable number of scans. Preliminary results indicate that at 24 Å2/molecule and 6 dyne/cm a heneicosanol monolayer is in a crystalline phase with highly ordered, mostly all- trans molecules, and at 42 Å2/molecule and 0 dyne/cm the monolayer consists of islands of the crystalline phase in coexistence with disordered molecules in a liquid phase. The good signal-to-noise ratio of the spectra obtained demonstrates the important role that nonimaging optics has in spectroscopy, by maximizing light throughput, and we make several suggestions for its implementation in other spectroscopic applications.
Sputtering Behavior of a Magnetron Glow Discharge Device
Authors: Shi Zhan , Woodrum Teresa Holbrook , Dehghan Khodayar , Brewer Stephen , Sacks Richard
Published: June 2005

The sputtering characteristics of a previously described dc planar magnetron glow discharge device are described for six different alloys and metals. Low-pressure linear etch rates of Cu-alloyed Al, steel, high-purity Cu, leaded brass, Al-alloyed Zn, and high-purity Ag and Au are found to be higher than those achieved with other planar magnetron devices. Direct mass-loss measurements, made from 0.0007 to 4.0 Torr pressure of Ar support gas at plasma currents varying from 50 to 400 mA, show that mass loss rates are generally greatest for the highest-atomic-number species at the highest currents and lowest pressures. Comparison of mass loss rates in pure Ar and 1/1 Ar/CF4 at low pressure shows enhancement of mass loss rates for Al and Ag in the mixture, but reduction of mass loss rates for Cu, brass, Zn, and Au in the mixture. Addition of CF4 to the Ar support gas results in significant quenching of numerous spectral features at both high and low pressures.
The Use of Singular Value Variance-Decomposition Proportions in FT-IR Analysis of Gases and Vapors
Authors: Battermanc Stuart
Published: June 2005

Issues in the application of spectral least-squares methods to Fourier transform infrared spectrophotometry are discussed with emphasis on collinearity problems in vapor and gas reference spectra. Excessive collinearity may degrade the accuracy and reliability of prediction. Several methods that detect and diagnose collinearity are developed and tested with the use of numerical experiments. The condition number is based on the singular values in the reference spectra matrix and provides a stable and composite measure of collinearity. Variance-decomposition proportions and auxiliary regressions identify the spectra that form dependencies. Application of the methods to spectra of common vapors and gases shows complex and potentially degrading dependencies that would not be seen by examining correlation coefficients or other statistics measuring only pair-wise dependencies. A method to estimate the precision of results for specified signal-to-noise ratios and degree of collinearity is evaluated.
Determination of Low Concentrations of the Azo-Dye Complex of Nitrite in Fresh Water and Seawater Using Surface-Enhanced Resonance Raman Spectroscopy (SERRS)
Authors: Xi Kang , Sharma Shiv K. , Taylor Gordon T. , Muenow David W.
Published: June 2005

A highly sensitive and selective method for the determination of low concentrations of nitrite in aqueous solutions using surface-enhanced resonance Raman spectroscopy (SERRS) is presented. The SERRS-active substrate was silver hydrosol. In order to induce the SERRS effect, nitrite was transformed into a colored product (an azo dye) by a standard chemical reaction. The detection limit for nitrite is 0.02 nM in distilled water, and analytical calibration curves yield straight lines in the concentration range below 30 nM. The sensitivity of this method is better than that of colorimetry and other techniques such as chemiluminescence. This improvement indicates that SERRS shows great promise as a useful analytical tool for trace analysis of nitrite and dyes.
Detection of Benzene and Trichloroethylene in Sooting Flames
Authors: Getty J. D. , Westre S. G. , Bezabeh D. Z. , Barrall G. A. , Burmeister M. J. , Kelly P. B.
Published: June 2005

The utility of resonance Raman spectroscopy as an analytical method is studied for application to multicomponent sooting flames. Far-ultraviolet resonance Raman spectra of benzene and trichloroethylene in methane diffusion flames have been obtained. The feasibility of flame temperature determination has been demonstrated for the benzene/methane flame. Resonance enhancement provides the sensitivity and selectivity required to detect low concentrations of aromatics and chlorinated hydrocarbons, in contrast to conventional spontaneous Raman spectroscopy, which suffers from low sensitivity and interference from laser-induced fluorescence of polycyclic aromatic hydrocarbons (PAHs).
Element Identification on the Surface of Inorganic Solids by Excimer Laser-Induced Emission Spectroscopy
Authors: Franzke D. , Klos H. , Wokaun A.
Published: June 2005

Intense atomic emission lines are observed when the surfaces of minerals, such as pyrite or zinc blende, are excited with UV laser pulses of 8 mJ energy, at a wavelength of 370 nm. The line spectra have been assigned to transitions of the metallic component of the material under investigation, in the neutral charge state of the corresponding atom; a few ionic emissions have also been detected. A nonlinear dependence of the emission intensity on incident laser energy, as well as the observation of transitions at energies higher than the incident photon energy, indicates that multiphoton processes are involved in the ablation and excitation process. The occurrence of the laser-induced emission phenomenon, at the pulse energies used, depends on characteristic properties of the material, such as absorption length, heat capacity, and enthalpy of vaporization. In the experiments, minor components contained in the naturally occurring minerals have been detected with high sensitivity. On the basis of this observation, the potential of the method for trace analysis has been explored. Test solutions containing an ion to be analyzed, such as Pb2+, have been applied to the surface of an ablatable copper or sulfur target. From the intensity of the recorded laser-induced Pb emission lines, a detection limit of less than 10 ppm or 35 mg/cm2 on the target has been deduced.
Combined Raman and Fluorescence Spectroscopy with the Same Compact CCD-Based Instrument
Authors: Hoffmann Günter Georg , Menzebach Hans-Ulrich , Oelichmann Bernhard , Schrader Bernhard
Published: June 2005

A compact CCD-based Raman and fluorescence spectrometer is described which allows detection of full Raman or fluorescence spectra without adjustment of the instrument.
Detection of Contaminants on Electronic Microcircuit Substrates by Laser Spark Emission Spectroscopy
Authors: Ottesen David K.
Published: June 2005

Laser spark emission spectroscopy is used to determine the elemental composition of contaminants found on electronic microcircuits fabricated on alumina substrates. This technique is particularly useful for rapid analyses of dielectric surfaces, and spatially resolved data with some degree of depth profiling information are obtained. Two specific examples are given which illustrate the utility of the method in pinpointing production problems.
Direct Determination of Thermophysical Parameter Kρc in Mayonnaise, Shortening, and Edible Oil
Authors: Bicanic Dane , Chirtoc Mihai , Dadârlat Dorin , Van Bovenkamp Pieter , Van Schayk Heidi
Published: June 2005

Inverse photopyroelectric (IPPE) spectroscopy, a novel variant among the photothermal spectroscopies, has been used for direct determination of ( Kρc)½ in a variety of food samples. The method appears capable of thermal characterization, and when combined with more mature techniques may prove useful in food products industry and storage.
X-Ray Photoelectron Spectroscopic Studies of Carbon Fiber Surfaces. Part XVI: Core-Level and Valence-Band Studies of Pitch-Based Fibers Electrochemically Treated in Ammonium Carbonate Solution
Authors: Xie Yaoming , Wang Tiejun , Franklin Oliver , Sherwood Peter M. A.
Published: June 2005

DuPont E-120 high-modulus pitch-based carbon fibers were treated electrochemically in 0.5 M (NH4)2CO3 solution under both potentiostatic and galvanostatic modes. X-ray photoelectron spectroscopy (XPS) was used to monitor the chemical changes on the carbon fiber surfaces. Both core-level and valence-band spectra showed that the treatment introduced both oxygen-containing and nitrogen-containing functional groups onto the fiber surfaces, and the mainly oxygen-containing functional groups produced were carbonyl (C=O) type functional groups after longer treatment time. For short treatment time, hydroxide (C-OH) type groups were the dominant functionality, and ether (C-O-C) or epoxide type groups were also formed. The O 2 s peaks from oxygen atoms in the hydroxide functionality and the ether or epoxide groups are well separated in the valence-band spectra; the corresponding O 1 s peaks, however, are not separated in the O 1 s core-region spectra.
Complexation of the Surfactants Triton X-102 and Igepal CA720 with β-Cyclodextrin
Authors: Smith Vonda K. , Ndou Thilivhali T. , Warner Isiah M.
Published: June 2005

The surfactants Igepal CA720 (IplCA7) and Triton X-102 (TX-102) and their interaction with β-cyclodextrin were studied with the use of various photophysical and photochemical methods. The fluorescence and absorbance spectra of these surfactants are concentration dependent and markedly enhanced in the presence of β-cyclodextrin. Nuclear magnetic resonance (NMR) spectroscopy infers that the phenyl group of these surfactants is included inside the β-CDx cavity. The orientation of the phenyl moiety of the surfactant molecule inside the β-CDx cavity was investigated with the use of induced circular dichroism (ICD).
XAFS Spectroscopy of Liquid and Amorphous Systems: Presentation and Verification of a Newly Developed Program Package
Authors: Ertel Teja Sebastian , Bertagnolli Helmut , Hückmann Sabine , Kolb Uwe , Peter Dietmar
Published: June 2005

A program package for XAFS data analysis, especially of liquid and amorphous samples, has been developed. For the first time a consequent error propagation is presented for all functions to be calculated in the course of the data analysis. The structural investigation of the Grignard compound CH3MgBr in diethyl ether is taken as an example for the various steps of the data analysis.
Influence of the Operating Mode of the Excitation Laser in Thermal Lens Spectrometry of Erythrosin in Water
Authors: Ecker A. , Georges J. , Mermet J. M.
Published: June 2005

This paper describes the behavior of erythrosin in thermal lens spectrometry. It is shown that the recovery of thermal energy released by the sample in aqueous solutions depends on the operating mode of the excitation laser (cw or pulsed). The results are discussed with respect to the time scales of sample irradiation and thermal lens formation.
Pre-Excitation, Catalytic Oxidation of Analytes over Hopcalite in Flame/Furnace Infrared Emission (FIRE) Spectrometry
Authors: Zhang Yunke , Busch Marianna A. , Busch Kenneth W.
Published: June 2005

Gas-phase infrared emission measurements made with the use of a new, specially designed, electrically heated furnace or a small hydrogen/air flame have shown that oxidation of a variety of carbon-based analytes to CO2 over the catalyst hopcalite prior to vibrational excitation in the furnace or flame markedly improves the response of the FIRE radiometer. Calibration curves obtained with the use of the furnace alone were generally nonlinear, while those obtained with the flame alone had slopes that were compound dependent. By the use of hopcalite in conjunction with the furnace, conversion to CO2 was significantly improved, and the FIRE response to pure acetone, benzene, dichloromethane, 1-chloro-2-methylpropane, heptane, methanol, and toluene became directly proportional to the number of moles of carbon introduced. In the case of the flame, as little as 0.1 g of hopcalite was sufficient to give a single, linear calibration curve (based on moles of carbon) for injection volumes of 0.2–1.0 μL of a test mixture composed of equal volumes of acetone, benzene, hexane, propanol, and tetrahydrofuran. With the use of hopcalite at its experimentally determined, optimum operating temperature of 380°C, an air flow rate of 45 mL min−1, and a furnace temperature of 600°C, the detection limit for hexane was found to be 518 ng C s−1. The use of hopcalite in conjunction with the flame (900°C) improved this detection limit by two orders of magnitude, due to the combined effects of an increase in excitation temperature and a decrease in source background noise. Injection of chlorinated compounds was found to temporarily poison the hopcalite, resulting in soot formation and loss of catalytic activity for periods of approximately ten minutes.
In situ Measurements of Infrared Reflection Absorption and Emission Spectra of Oxide Film Formed on Chromium Metal at Temperatures up to 973 K
Authors: Honda Katsuya , Atake Tooru , Saito Yasutoshi
Published: June 2005

An apparatus has been constructed for in situ measurements of infrared reflection absorption and emission spectra. Chromium metal oxidized at 973 K in air for 25 min was investigated at various temperatures up to 973 K. The frequencies of the bands shifted toward the lower wavenumber range with increasing temperature. In situ measurements were made for isothermal oxidation of chromium at 773 K.
Versatile and High-Repetition Subnanosecond Light Source for Fluorescence Lifetime Measurements
Authors: Araki Tsutomu , Hanabusa Nobuhiro , Uchida Teruo , Wang Xue F. , Minami Shigeo
Published: June 2005

We describe the construction and emission characteristics of a gap-adjustable, capacitor-replaceable pulsed light source (air-discharge type) that produces high-repetition pulsed UV light of nanosecond duration. Stable light pulses of 0.8 to 3.5 ns width are generated from atmospheric-pressure air discharge between the sharp anode and round cathode. Appreciable heterogeneities on the distribution of emission intensity and its on-set timing along the discharge gap were observed. Fluorescence lifetimes of ethidium bromide solutions were measured to demonstrate the usefulness of the light source.
In vivo Skin Reflectance of the Wall Lizard, Podarcis Muralis
Authors: Bacci Mauro , Lanza Benedetto , Linari Roberto , Tosini Gianluca
Published: June 2005

A portable optical-fiber spectrum analyzer operating in the visible and near-infrared range was used to measure in vivo the skin reflectance of lizards of the genus Podarcis. The investigations, which we performed in connection with a study of the biological problem of the microinsular melanism, are quite safe for the examined animals and can be easily extended to spectroscopic and/or energy input studies in other animals.
Solid-Matrix Luminescence Polarization of p-Aminobenzoate Adsorbed on Sodium Acetate and Sodium Acetate/Sodium Chloride Mixtures
Authors: Ramasamy S. M. , Hurtubise R. J.
Published: June 2005

Luminescence polarization values for the anion of p-aminobenzoic acid adsorbed on sodium acetate were obtained over a wide temperature range. Also, luminescence polarization values were obtained for p-aminobenzoate on a variety of sodium acetate/NaCl mixtures at 296 and 93 K. For the anion of p-aminobenzoic acid adsorbed on sodium acetate, the fluorescence and phosphorescence polarization values were essentially constant with temperature. The phosphorescence polarization data indicated that the anion of p-aminobenzoic acid did not undergo rotational relaxation over the temperature range investigated; thus rotational processes did not contribute to nonradiative deactivation. Vibrational processes were primarily responsible for the decrease in phosphorescence quantum yields as the temperature increased. For the luminescence polarization data with the sodium acetate/NaCl mixtures, little change was observed for both the fluorescence polarization data and phosphorescence polarization data at the two different temperatures. These data indicated, along with earlier luminescence quantum yield data, that the three-dimensional bonding characteristics of the solid-matrix are very important in obtaining a high luminescence yield.
Improved Intensity Formulae for the Determination of Rotational Temperature from the Perturbed Band Structure
Authors: Serine Shigeyuki , Hamaya Tsuyoshi , Hirose Chiaki
Published: June 2005

Improved formulae for the intensity profile of the rotational lines have been derived for the [ ndσΣ+, ndπII, ndδΔ] (Hund's case d)- n'pπII (case b) electronic bands of diatomic molecules with respect to the l-uncoupling interaction among the upper states. As an application of the formulae, the rotational temperature in the dc discharge plasma was determined from the analysis of the band structure of the He2[3 dσf3Σ+ u, 3 dπf3II u, 3 dδf3Δ u] ← 2 pπb3II g (0-0) absorption bands. The formulae were also applied to the H2 [3 dσg3Σ+ u, 3 dπi3II u, 3 dδj3Δ u] → 2 pπc3II g (0-0) emission bands.
Collection Angle Dependence of the Depolarization Ratio in Light-Scattering Experiments
Authors: Teboul V. , Godet J. L. , Le Duff Y.
Published: June 2005

We have calculated, in a typical scattering experiment, the exact value of the intensity scattered by a sample for any value of the collection angle of the scattered beam and for different beam polarizations.
Electrospray Mass Spectrometry as a Technique for Elemental Analysis: Preliminary Results
Authors: Agnes George R. , Horlick Gary
Published: June 2005

Preliminary results for the analytical use of electrospray mass spectrometry (ES-MS) for elemental analysis are presented. Spectra with the declustered plus-one ion (M+) as the dominant species have been measured for the alkali metals (Li, Na, K, Rb, and Cs) and for several transition metals (Cr, Mn, Fe, Co, Ni, Cu, Zn, Ag, and Cd) in both aqueous and methanol solvents. A number of background ions are also observed including MH+, MO+, MOH+, and MOH(H2O)+. For vanadyl sulfate and uranyl nitrate, ES conditions can be adjusted to produce VO+ and UO2+ as the dominant ions in the mass spectra, indicating that direct speciation of inorganic solution components is possible. On the basis of these preliminary results, it appears that electrospray may offer a low-cost and simple generic ion source for elemental mass spectrometry.
Pressure and Density Dependence of the CH4 and N2 Raman Lines in an Equimolar CH4/N2 Gas Mixture
Authors: Fabre D. , Oksengorn B.
Published: June 2005

Experiments have been performed to determine the variations of the peak area for the CH4 and N2 Raman lines along with their frequency shift and broadening, as a function of pressure and density, in the case of an equimolar CH4/N2 gas mixture. A comparison is made between the relative values of the Raman scattering cross sections for the two species and the values of the internal field term, versus density of the mixture, showing that the density dependences of these physical quantities become more dissimilar as density increases. Moreover, the ratio of the peak areas for the CH4 and N2 Raman lines is found to be constant in the entire pressure range used. From a practical point of view, these results for gas mixtures could be useful in quantitative analysis of fluid inclusions in rocks.
Chemical Attack of Graphite/Epoxy by Hydrogen Peroxide
Authors: Sloan Forrest E.
Published: June 2005

Techniques for studying the mechanisms of chemical corrosion in fiber-reinforced plastics are of considerable importance. The most common analysis technique for studying chemical changes in polymers is Fourier transform infrared (FT-IR) spectroscopy. For polymers reinforced with graphite fibers, however, study of the matrix is hindered by the presence of the graphite, which strongly absorbs IR radiation in a broad band of wavelengths. The purpose of this study was to investigate the degradation of AS-4/3501-5a graphite/epoxy composite material exposed to solutions of hydrogen peroxide. Evidence was also sought for degradation in high pH (up to pH = 12) solutions. After long-term environmental exposure, a simple gravity flotation technique was used to separate the epoxy matrix from the graphite fibers for FT-IR analysis. The resulting spectroscopic evidence indicates that hydrogen peroxide attacks the secondary amines in the cured epoxy structure. No evidence of attack by high pH solutions was found.
Two-Dimensional Vibration Spectroscopy: Correlation of Mid- and Near-Infrared Regions
Authors: Barton F. E. , Himmelsbach D. S. , Duckworth J. H. , Smith M. J.
Published: June 2005

A novel approach, utilizing a two-dimensional (2D) statistical correlation of mid- and near-infrared spectra, is presented as a means to assist with qualitative spectral interpretation. The method utilizes cross-correlation by least-squares to assess changes in both regions that result from changes in sample composition. The technique has been applied to complex agricultural samples that differ in wax (cuticle), carbohydrate, protein, and lignin content. Dispersive near-infrared (NIR) and interferometric mid-infrared (FT-IR) diffuse reflectance spectra were obtained on each of the samples, and point-for-point 2D cross-correlation was obtained. The technique permits the correlation of the combination and overtone region of the NIR to the fundamental vibrations in the mid-infrared (MIR) region. This allows the determination of the most probable source of NIR signals and verification of the “real” information content of the purely statistically derived signals whose intensities currently are used for quantitative analysis in this spectral region.
First Observation of the Urbach Tail in a Multicomponent Organic System
Authors: Mullins Oliver C. , Zhu Yifu
Published: June 2005

The exponential attenuation of electronic absorption in spectral regions removed from the absorption maxima, the “Urbach tail,” has been observed in a variety of materials and has been ascribed to thermal and structural disorder. Here, we report, to our knowledge, the first observation of the Urbach tail in a multicomponent organic system (the asphaltenes) which is due, in part, to the overlapping absorption spectra of the diverse component chromophores within the tail spectral region. The distribution of chromophores produces an unusually large, nonthermal width in the Urbach tail.
Fourier Transform Infrared Spectrometry/Attenuated Total Reflectance Study of the Reaction of Pentanal and Propanal with 2-(Hydroxymethyl)Piperidine
Authors: Kennedy Eugene R. , Ashley Kevin
Published: June 2005

The reactions of propanal and pentanal with 2-(hydroxymethyl)piperidine were investigated by Fourier transform infrared spectrometry/attenuated total reflectance in both the solution phase and at the gas/solid interface. The reactions were studied with the use of a flow-through cylindrical internal reflection (“circle”) cell. Reaction intermediates were tentatively identified by their characteristic infrared absorption frequencies. At the gas/solid interface the reaction is thought to yield a hemiaminal intermediate. In the solution phase a hemiaminal intermediate is believed to form initially, followed by loss of water to generate an enamine product. In both gas-phase and solution-phase studies, an oxazolidine product is prepared only after an ultrasound treatment. The FT-IR/ATR technique reveals detailed mechanistic information concerning reactions between aldehydes and ethanol amines.
Lignin Determination by FT-IR
Authors: Friese Michael A. , Banerjee Sujit
Published: June 2005

The lignin content of pulp is determined from its diffuse reflectance infrared spectrum by an algorithm that calculates the degree of overlap between two spectra. The lignin:cellulose fraction correlates with kappa number, a titrimetric measure of lignin. Essentially no sample preparation is required, and the procedure is insensitive to variations in moisture content. The algorithm is able to detect changes induced by exposure of pulp to NO2.
A Novel Fiber-Optic-Based Pump-Probe Instrument for the Acquisition of Kinetic Information
Authors: Carroll Mary K. , Hieftje Gary M.
Published: June 2005

A pump-probe instrument is described that utilizes two beams from the same laser and a fiber-optic-based sample cell for low-temperature measurements. The utility of this instrument is demonstrated through an examination of the excited-state kinetics of 2,7-diphenylphenanthrene, for which the rate constant of singlet-to-triplet intersystem crossing is found to be approximately 8 × 105 s−1. This molecule is interesting in that it undergoes an unusual rotational conformation change in the triplet state with a rate constant of 2.4 × 108 s−1 at 77 K.
Eu3+ Ion Luminescence Spectra from Lanthanide Sesquioxides Exhibiting Three Different Crystal Structures
Authors: Chen G. , Haire R. G. , Peterson J. R.
Published: June 2005

We have investigated the Eu3+ ion luminescence spectra from different host crystals of the lanthanide sesquioxides exhibiting either the A, B, or C form. The Eu3+ ion luminescence spectra from B-type Eu2O3 and from Eu3+-doped A-type La2O3 and C-type Lu2O3 were obtained at room temperature. It is suggested that the luminescence from f-f transitions in the Eu3+ ion can be used to determine the crystal structure, because the different Eu3+ ion site symmetries in the different crystal structures give rise to different characteristic spectral splitting patterns.
Scanning Multichannel Technique for Improved Spectrochemical Measurements with a CCD Camera and its Application to Raman Spectroscopy
Authors: Deckert V. , Kiefer W.
Published: June 2005

In continuation of work performed with the application of the scanning multichannel technique in combination with a photodiode array and a single monochromator we show in the present paper a similar technique combining a CCD camera with a double monochromator system with additive dispersion. Special emphasis is given to a discussion of the reproduction of spectral features with small bandwidth. Examples of applications of this technique are given in terms of high-resolution Raman spectroscopy of gases. This technique is not restricted to this type of optical spectroscopy, but can be universally applied to all spectroscopic methods where CCD detection is used.