bluuebunny/crossref_metadata_2025 huggingface dataset:
Analysis of Mixtures of Coal-Derived Phenols by 19F NMR of Hexafluoroacetone Adducts
Authors: Bartle Keith D. , Matthews Raymond S. , Stadelhofer Jürgen W.
Published: August 2005

19F nuclear magnetic resonance chemical shifts are reported for the hexafluoroacetone adducts of 21 phenols commonly found in coal-derived mixtures. Signals for the adducts of certain phenols not readily separated by gas chromatography, such as the three cresols, are well resolved. Analysis of coal-derived phenol fractions by this procedure is simple and quantitative as long as 2,6-disubstituted compounds are not present, and the mixtures are not too complex.
Some New Solid Electrolytes: Substituted Organic Ammonium Silver Iodides
Authors: Ferraro John R. , Walling Priscilla Labonville , Sherren Anne T.
Published: August 2005

Several new solid electrolytes were synthesized from the reaction of substituted organic ammonium hydroiodides (pyridinium and quinolinium type) and varying quantities of silver iodide. The inductive effects of nucleophilic and electrophilic substitution on the pyridinium or quinolinium ring, as well as substituent position on the ionic conductivity, were determined. Pressure and thermal studies were undertaken to determine if new nonambient conductive phases existed.
The Determination of Raman Excitation Profiles of Adenine Derivatives in the 285 to 320 nm Region
Authors: Bushaw T. H. , Lytle F. E. , Tobias R. S.
Published: August 2005

Experimentally determined Raman excitation profiles are reported for adenosine monophosphate (AMP), adenylyl-(3′ → 5′)-adenosine, and polyadenylic acid. Excitation in the ultraviolet is restricted to the preresonance region to avoid the necessity for inclusion of linewidth factors in the theoretical fit to the experimental data. The effective absorption wavelengths from which the three most intense vibrations derive their intensities are determined. For each vibrational mode, no appreciable difference in the excitation profiles of each of these systems is observed, but the results for AMP are found to differ from those previously reported. The utility of these measurements with respect to conformational studies is discussed.
Optical Analysis of 12C/13C and 12C/14C Ratios in Carbon Dioxide, by Measurements on the CO+ Spectrum in the Wavelength Interval between 210 and 250 nm
Authors: Johansen H. Saaby , Middelboe V.
Published: August 2005

Optical analysis of carbon isotopes by emission spectroscopy has been investigated by measuring the first negative band system of CO+. The optical analysis for the abundances of carbon-13 and carbon-14 can be carried out with a SD of 0.05 at. %.
Raman Measurements on Thin Polymer Films and Organic Monolayers
Authors: Rabolt J. F. , Santo R. , Swalen J. D.
Published: August 2005

Resonant and nonresonant Raman scattering measurements have been obtained from very thin (27 Å to 1 μ) films of long chain organic molecules and polymers using multilayered integrated optics. The increased optical field intensity within the film together with an increase in scattering volume enable high signal/noise spectra to be obtained. Investigation of a single cyanine dye monolayer using the Resonance Raman effect has revealed frequency shifts of the quinoline in plane C—C and C—N stretching modes at 1392 and 1366 cm−1 resulting from intermolecular adhesive forces at the film-Corning glass interface. Bandwidth broadening of these modes indicates a distribution of chromophore environments at the glass surface possibly reflecting the heterogeneity of surface binding sites.
Infrared Intensity Measurements of Cryodeposited Thin Films of NH3, NH4HS, H2S, and Assignments of Absorption Bands
Authors: Ferraro John R. , Sill G. , Fink U.
Published: August 2005

Interferometric infrared spectral transmission measurements from 60 to 10 000 cm−1 were made for thin films of NH3, NH4HS, and H2S cryodeposits, and recorded as a function of thickness and temperature from 88 K to evaporation points. Integrated band intensities were measured and are reported for all major absorptions. Assignments for lattice and internal fundamental modes are discussed. Particular attention is devoted to the various reported phases of solid NH3, and it is concluded that three phases are supported by experimental evidence: the stable cubic phase, a low temperature amorphous phase, and an intermediate temperature metastable phase. Results and changes of the spectra as a function of temperature will be summarized. Intercomparisons of the spectra obtained for the three cryodeposits are made.
Quantitative Infrared Absorption Measurements on Tri-n-Butyl Phosphate
Authors: Tomaselli Vincent P. , Zarrabi Hassan , Möller K. D.
Published: August 2005

The molar absorptivity, ε(ν̄) of three intense infrared absorption bands in tri- n-butyl phosphate has been measured as a function of concentration. For all three bands, ε(ν̄) is independent of concentration for dilute solutions, then decreases uniformly with increasing concentration, and finally becomes independent of concentration again as one approaches the pure liquid. A saturation effect is found at about 1.0 M for all cases. Deviations from Beer's law behavior are observed at concentrations which depend upon the absorption band and/or the choice of nonpolar solvent. Self-association of the solute molecules is considered to be the cause of the decrease in ε(ν̄) with increasing concentration. From the measured data, it is possible to estimate the number of solvent molecules required to prevent this self-association. For CCl4, we find this value to be 25 molecules of solvent per solute molecule, a value in agreement with elementary geometric consideration.
Analysis of Sensor-Lance Samples for Basic Oxygen Furnace Control
Authors: Linde T. R.
Published: August 2005

As part of a new basic oxygen furnace (BOF) steelmaking control system, procedures were developed for rapidly handling and accurately analyzing steel samples taken with a sensor-lance from an upright vessel. Determinations must be: (1) accurate to control the steelmaking process and assure that the heats are made to specifications, and (2) rapid to reduce BOF turnabout time and thus provide the potential to increase productivity. A pneumatic tube carrier was developed to safely transport hot (2200°F) lance samples to the laboratory. The samples are cut and cooled simultaneously on a high-speed abrasive cutoff machine equipped with a specially designed sample clamp and a high-volume water cooling system. Initially, the analytical performance was not as good as that obtained from conventional cast disk samples. Analysis deviations were traced to large slag-type sulfur-bearing inclusions in the lance samples. Accurate analyses were then obtained by increasing the spectrometer preburn time from 3 to 15 s. More than 1000 trial heats have been made. The procedures we developed permit hot samples to be removed from the lance sampler, sent to the laboratory, analyzed, and reported in about 3 minutes.
Multicomponent Photochemical Studies by Rapid Scanning Fluorescence Spectroscopy
Authors: Fogarty Michael P. , Warner Isiah M.
Published: August 2005

A novel technique for initiating and probing photochemical reactions is described. The technique involves the use of a video fluorometer for polychromatic sample illumination. This polychromatic illumination provides the energy for photo-induction of the monitored reaction as well as a method for simultaneously monitoring the excitation and emission spectra of all fluorescing species in the reaction. The advantages of this multicomponent approach are discussed using the photo-induced reactions of anthracene in polychlorinated alkanes as an example.
Use of Thermal Blooming Spectroscopy for Enzymatic Analyses
Authors: Haushalter Jeanne P. , Morris Michael D.
Published: August 2005

Thermal blooming has been used to measure weak absorption. The thermal lens was generated with a chopper ion laser (488 nm) and monitored with a helium-neon laser, using lock-in detection. The generation of dopachrome by enzyme-catalyzed air oxidation of dopamine was monitored as the rise of the dopachrome absorption signal. Dopamine concentrations were found to be proportional to initial slopes. Modifications to the existing apparatus to improve detection limits are suggested.
Composition of Mixtures of Natural Gas Components Determined by Raman Spectrometry
Authors: Diller Dwain E. , Chang Ren Fang
Published: August 2005

The feasibility of using Raman spectrometry for determining the composition of mixtures of natural gas components was examined. Raman intensity measurements were carried out on eight, gravimetrically prepared, binary gas mixtures containing methane, nitrogen, and isobutane at ambient temperature and at pressures to 0.8 MPa. The repeatability of the molar intensity ratio, ( I2/ y2)/( I1/ y1), where y1 is the concentration of component 1 in the mixture, and I1 is the intensity of the related line in the mixture spectrum, was examined. The compositions of two gravimetrically prepared methane-nitrogen-isobutane gas mixtures were determined spectrometrically with an estimated precision of about 0.001 in the mole fraction. Typical differences from the gravimetric concentrations were less than 0.002 in the mole fraction. The Raman spectrum of a gravimetrically prepared, eight component, hydrocarbon gas mixture was obtained to show that the Raman spectrometric method has potential for being applicable to natural gas type mixtures.
Evaluation of a Multichannel Inductively Coupled Plasma-Optical Emission Spectrometer Modified to Minimize and Correct Scattered Light Effects
Authors: Taylor Charles E. , Floyd Terrance L.
Published: August 2005

In a study of an inductively coupled plasma optical emission spectrometer, data from an early commercially available instrument are compared with data from the same instrument after modifications to correct observed inadequacies. Results show negligible changes in powers of detection but considerable reductions in scattered light interferences following the installation of a holographic grating.
The Shape of Analytical Curves in Zeeman Atomic Absorption Spectroscopy. II. Theoretical Analysis and Experimental Evidence for Absorption Maximum in the Analytical Curve
Authors: De Loos-Vollebregt M. T. C. , de Galan L.
Published: August 2005

The analysis of the shape of analytical curves in Zeeman atomic absorption spectroscopy has been extended toward higher concentrations. Nonlinearity in the conventional atomic absorption signal due to stray light or nonlinear electronic response causes both theoretically calculated and experimental analytical curves in Zeeman atomic absorption to go through a maximum at a certain concentration. The height and the position of the maximum depend on the magnetic system used, the strength of the magnetic field and the amount of nonlinearity. In all magnetic systems the maximum attainable absorbance is enhanced by increasing the magnetic field strength and decreasing the amount of nonlinearity. Over the normal concentration range a maximum in the Zeeman atomic absorption analytical curve only occurs under the extreme conditions of a very weak magnetic field and strong nonlinearity. Ultimately, however, all Zeeman atomic absorption analytical curves pass through a maximum unless the optics and electronics are perfect. For practical systems strong ac modulated magnetic fields are to be preferred over dc magnetic fields.
Photoacoustic Infrared Spectra (IR-PAS) of Aged and Fresh-Cleaved Coal Surfaces
Authors: Rockley Mark G. , Devlin J. Paul
Published: August 2005

The application of the newly developed technique of photoacoustic infrared spectroscopy, using a Fourier transform infrared spectrometer, to the measurement of the infrared spectra of single slabs of various coal types is described. The effects of aging of coal surfaces, which include both oxidation and abrasion, are clearly apparent in a comparison of the spectra of freshly cleaved and aged coal surfaces.
Raman Spectra of Light-Coupling Prism and Gemstone Materials
Authors: Griffiths J. E. , Nassau K.
Published: August 2005

Materials potentially useful as prism coupling components for the study of the properties of thin films have been characterized by their Raman spectra. Diamond emerges as the material of choice from a group including diamond, cubic zirconia, rare earth garnets, strontium titanate, rutile, sapphire, spinel, silicon carbide, beryls, yttralox and topaz. Several of these materials are used as diamond imitations and are readily identified from their Raman spectra. Doublets and their components are also readily identifiable.
Molecular Emission Spectra in the Radio-Frequency-Excited Inductively Coupled Argon Plasma
Authors: Reeves R. D. , Nikdel S. , Winefordner J. D.
Published: August 2005

Emission spectra of the molecules OH, NO, and NH have been studied in the argon inductively coupled plasma (ICP) as a function of height in the plasma, input power, and environment adjacent to the plasma. Similar studies were carried out with an ICP into which solutions of elements forming stable monoxides, such as Sc, Y, Gd, and Zr, were introduced.
Application of a Search System and Vapor-Phase Library to Spectral Identification Problems
Authors: Erickson Mitchell D.
Published: August 2005

A recent major advance in the field of gas chromatography/Fourier transform infrared spectrometry is the availability of a search system and digitized vapor phase infrared library. This paper presents the results of the application of this search system to a real-world sample. Examples are shown of correct matches and an incorrect match. Overall, the search performs very well with good quality unknown spectra, but cannot differentiate between a spectrum and background. These results indicate that visual comparison of the unknown and standard are required for all but the most routine identifications.
A Background Emission Correction System for Atomic Absorption Spectrometry
Authors: Dewalt Frederic G. , Amend John R. , Woodriff Ray
Published: August 2005

A simple system which corrects for both broad band absorption and broad band emission in thermally atomized atomic absorption spectroscopy is presented in this article.
Quantitative Analysis of a Binary Mixture by Fourier Transform Infrared Photoacoustic Spectroscopy
Authors: Rockley Mark G. , Davis Dennis M. , Richardson Hugh H.
Published: August 2005

The isotopic shift of the v2 NO3−1 absorption of mixtures of K15NO3 and K14NO3 at 800 and 825 cm−1 has been used to demonstrate that Fourier transform infrared photoacoustic spectroscopy is a technique which is useful for quantitative analysis of solid mixtures.
Rapid Scan Inverse Raman Spectroscopy
Authors: Buffett Clifford E. , Morris Michael D.
Published: August 2005

Inverse Raman spectra are obtained at 1 cm−1 resolution at scan rates of 330 cm−1/min with good signal/noise ratio. Scan rates are limited by grating rotation speed of the dye laser. It is proposed that a dye laser designed for rapid tuning would allow scan rates above 1000 cm−1/min with no loss of resolution or signal/noise ratio.
Comparison of Nebulization-Spray Chamber Arrangements for Atomic Fluorescence and Atomic Emission Flame Spectrometry
Authors: Horvath J. J. , Bradshaw J. D. , Winefordner J. D.
Published: August 2005

Ten different commercial atomic absorption nebulizer-chamber systems with a capillary burner and three laboratory-constructed ultrasonic nebulizer chamber systems with a miniflame burner are compared with respect to solution uptake rates, concentrational and absolute detection limits, efficiencies of nebulization, and common flame spectrometric interferences. Measurements of both flame atomic emission (Sr, Ca, K, Na) and flame atomic fluorescence (Mg, Cu, Pb) were performed for all cases. The ultrasonic and pneumatic nebulizer systems resulted in about the same concentrational detection limits, but the former resulted in ∼102X lower absolute detection limits. The batch type ultrasonic nebulizer gave much higher nebulization efficiencies than the continuous flow ultrasonic nebulizer or any of the pneumatic nebulizer systems. Chemical interferences were approximately the same in all nebulizer-burner systems. Nebulizer chambers with a J-bead resulted in lower detection limits than the same systems without J-beads.
Some Observations on Perchloric Acid Interferences in Furnace Atomic Absorption
Authors: Koirtyohann S. R. , Glass E. D. , Lichte F. E.
Published: August 2005

Many digestion and dissolution procedures produce a sample solution several tenths molar in perchloric acid. This amount of acid suppresses the furnace atomic absorption signal for many elements. The group 3A elements are particularly severely suppressed. 0.5 M HClO4 causing over 95% reduction in peak absorbance for Al, Ga, and Tl, The effect persists even though the furnace tube is heated far above the HClO4 boiling point during the ashing portion of the furnace cycle. Heating to about 1700°C is required to completely remove the residual effect. The analyte is vaporized at the proper stage in the furnace cycle but escapes in molecular form rather than being atomized. Perchloric acid or one of its decomposition products apparently interacts with the graphite to form a thermally stable product which later decomposes and inhibits atomization. The suppression can be reversed by addition of certain organic compounds such as sucrose or formic acid or by addition of excess ammonium carbonate or ammonium sulfate.
Properties of Digital Smoothing Polynomial (DISPO) Filters
Authors: Ziegler Horst
Published: August 2005

Digital filters for spectrometric applications are compared with the classical RC filter. Properties discussed include noise reduction, line shift, and conservation of line moments. For Gaussian and Lorentzian lines, signal deformation and change of half-width as a function of time constant and line width are calculated for several filter types. Using accuracy, sensitivity, and scan speed as criteria, it is shown that a fourth-order digital smoothing polynomial (DISPO) filter is better by typically 1 or even 2 orders of magnitude than the RC filter. Since a real time implementation of these filters is possible, they can directly replace RC filters in all spectrometric applications.
On the Use of the Inverted Abel Integral for Evaluating Spectroscopic Sources
Authors: Algeo J. D. , Denton M. B.
Published: August 2005

A numerical method for evaluating the inverted Abel integral employing cubic spline approximations is described along with a modification of the procedure of Cremers and Birkebak, and an extension of the Barr method. The accuracy of the computations is evaluated at several noise levels and with varying resolution of the input data. The cubic spline method is found to be useful only at very low noise levels, but capable of providing good results with small data sets. The Barr method is computationally the simplest, and is adequate when large data sets are available. For noisy data, the method of Cremers and Birkebak gave the best results.
Observation of Charge Transfer Complex Orientational Phase Transitions by Means of Fourier Transform Infrared Spectroscopy
Authors: Cameron D. G. , Umemura J. , Williams D. F.
Published: August 2005

Fourier transform infrared spectroscopy was used to monitor the ∼200 K order-disorder phase transition of anthracene-h10: tetracyanobenzene and anthracene-d10:tetracyanobenzene charge transfer complexes. It was shown that the technique is sufficiently sensitive to monitor the temperature of transition and to study the transition via the infrared active internal vibrational modes.
Low Temperature Air Oxidation of Caking Coals: Fourier Transform Infrared Studies
Authors: Painter P. C. , Coleman M. M. , Snyder R. W. , Mahajan O. , Komatsu M. , Walker P. L.
Published: August 2005

Fourier transform infrared spectroscopy has been used to characterize the oxidation of a coking coal. The results demonstrate that the most important initial products of oxidation are carbonyl and carboxylic acid groups. Bands associated with carbon-oxygen single bonds, as in ethers or phenols, do not become prominent until the later stages of the oxidative process. Upon reaction with potassium in tetrahydrofuran a number of changes in the spectrum of both the oxidized and unoxidized coal become apparent. This reagent cannot be considered specific for cleavage of ether bonds, but can also lead to products usually associated with air oxidation.
Thermally Assisted Fluorescence: A New Technique for Local Flame Temperature Measurement
Authors: Zizak G. , Bradshaw J. D. , Winefordner J. D.
Published: August 2005

The theoretical basis of a new technique called thermally assisted atomic fluorescence for measurement of local spatial-temporal flame temperatures is given. In this method, the ratio of fluorescence signals from a radiatively excited level and a higher collisionally excited level or from two higher collisionally excited levels of an inorganic probe, such as In or TI, is related to the flame temperature. The conditions necessary for the measured flame temperature to be identical to the translational (Boltzmann) flame temperature are given. The experimental system and conditions for making flame temperature measurements, which consists basically of a single pulsed dye laser and a gated detector, are described. The assumption of steady-state conditions is discussed as well as several anomalies in terms of fluorescence from certain energy levels of Tl. The accuracy and precision of the measured flame temperatures for several methane-air flames are discussed.
Miniature High Temperature Laminar Diffusion Flames for Analytical Atomic Spectrometry
Authors: Hughes S. K. , Fry R. C.
Published: August 2005

Miniature high temperature laminar diffusion flames are described for analytical atomic spectrometry. Fuel flow rates below 0.2 liters/min are used and temperatures in excess of 2500 K are maintained in a stable, fuel-rich combustion environment of low background emission. The internal atomizer chamber volume is 1.5 ml (below the burner top). A graphite cup atomizer is used for sample introduction and is “fired” inside the miniature burner head in the presence of “fuel only.” Oxidant diffuses into the fuel zone above the burner top. Compared to conventional electrothermal atomizers, the miniature N2O → H2 diffusion flame greatly reduced particulate light scattering in continuum excited atomic fluorescence spectrometry. In atomic absorption spectrometry, the hot miniature flame serves to effectively reduce the molecular spectral interference due to gaseous diatomic alkali halides. The enhanced gas phase concentration of atomic products presently results in a concentration sensitivity improvement of 30 times over conventional premixed flames used in Eimac continuum excited atomic fluorescence. The improvement in absolute weight sensitivity is 140 times for atomic fluorescence.
Excitation Temperatures in the Hollow Cathode Discharge
Authors: Mehs D. M. , Niemczyk T. M.
Published: August 2005

Excitation or spectroscopic temperatures have been determined for various operating conditions of a hollow cathode discharge. It was found that the temperatures measured do not significantly change over the range of conditions studied. These results are compared to those obtained in other low-pressure discharges. The temperature values as well as trends are found to be very similar.
Factor Analysis and Fourier Transform Infrared Spectra of Compatible Blends of Polyphenylene Oxides and Polystyrene
Authors: Koenig J. L. , Rodriquez M. J. M. Tovar
Published: August 2005

Fourier transform infrared spectra has been obtained of compatible blends of polyphenylene oxide (PPO) and polystyrene (PS). An incompatible blend of polyphenylene oxide and poly(4-chlorostyrene) (P4C1S) was also studied. Factor analysis was used to determine the number of components in the blend system. The data indicated that three components existed in the PPO/PS compatible system and only two in the PPO/P4C1S system. The interaction spectrum in the compatible blend was determined by a double-subtraction technique and used to analyze the blend system for the magnitude of the interaction as a function of composition. The interaction was maximum at a 70/30 composition in agreement with other data.
Some Applications of Fourier Transform Infrared Photoacoustic Spectroscopy
Authors: Krishnan K.
Published: August 2005

A new photoacoustic cell for use with Fourier transform infrared spectrometers is detailed. Photoacoustic infrared spectra showing high sensitivity on a variety of chemical systems are presented. Comparison of the photoacoustic infrared spectra with transmission and attenuated total internal reflectance spectra show that saturation effects can play a prominent role in the photoacoustic spectra. Spectral subtractions and study of the situ chemical reactions are possible using the photoacoustic technique. The photoacoustic and diffuse reflectance techniques yield very similar spectra.
Infrared Linewidth and Line Position Measurements Using Diode Lasers with Internal Calibration
Authors: Chang Tsu-Yen , Morris Rex N. , Yeung Edward S.
Published: August 2005

Measurements in the infrared region using semiconductor lasers, particularly as applied to atmospheric pollution monitoring, depend critically on the availability of reliable line positions and linewidth information. We demonstrate a unique internal calibration technique such that spectral locations can be determined accurately, to the order of the monochromaticity of the laser. This is based on low-pressure absorption measurements and subsequent fitting of a Voigt profile and determining the Doppler component. With this technique, we are able to determine the self- and the N2-broadening parameters of the NH3 line at 852.7 cm−1 to be 26.2 ± 0.4 MHz Torr−1 and 5.2 ± 0.1 MHz Torr−1, respectively. Also, the spectral locations for several SO2 lines in the 1180.1 cm−1 region were determined accurately.
Processor-Controlled Microdensitometry
Authors: Ewbank J. D. , Bowers P. , Pinegar J. , Schafer L.
Published: August 2005

A new scheme of densitometric data collection is described which comprises a digital filtering technique and process control program. A 6502-based PET 2001/32K microcomputer and an Elscan model 2500 specular microdensitometer are interfaced through the standard 6522 VIA port chip. An Analog Devices ADC80/12 monolithic A/D converter is used to digitize the analog output of the light photometering system. Additionally, control of the optical scanner assembly is provided through processor-driven 4-phase TTL logic circuitry. The technique applies to any analog signal of interest, either for filtering purposes or for recording directly into memory for later waveform or transient analysis. The maximum data gathering rate is 40 kHz, limited by the A/D conversion time of 25 μs.
Computer-Controlled Absorption, Fluorescence, and Coherent Anti-Stokes Raman Spectrometry for Liquid Chromatographic Detection
Authors: Boutilier G. D. , Irwin R. M. , Antcliff R. R. , Rogers L. B. , Carreira L. A. , Azarraga Leo
Published: August 2005

A computer-controlled liquid chromatograph is described using two pumps for gradient elution. An absorption, fluorescence, and fluorescence-excitation detection system is centered around a silicon intensified target Vidicon detector. This allows fluorescence and absorption spectra to be recorded and stored every 3 s without stopping flow. A coherent anti-Stokes Raman spectrometer is also used in series in the detection scheme. This overall system allows great flexibility and the acquisition of a large amount of data from a single separation.
High-Temperature Raman Spectra of CO2 and H2O for Combustion Diagnostics
Authors: Stephenson David A.
Published: August 2005

The Raman spectra of CO2 and H2O have been measured from 1000 to 2200°K. The spectra are found to be well described by the simple models described previously. In particular, the simple partition functions of T−1 for CO2 and T−3/2 for H2O are adequate for describing the spectra over the temperature range of interest.
Accurate Wavelength Calibration of an Etalon-Tuned Dye Laser
Authors: Beenen G. J. , Hosch J. W. , Piepmeier E. H.
Published: August 2005

A method to set accurately an etalon-tuned dye laser to any preselected wavelength within its lasing region is presented. The method involves a unique procedure to determine accurately the etalon thickness, so that the correct etalon order can be found for each wavelength and corresponding etalon setting. An equation relating the dial reading on the optical mount of the intracavity etalon to lasing wavelength is derived and evaluated for the Chromatix CMX-4 pulsed tunable dye laser. The procedure used to evaluate the equation parameters is described in detail. After establishing the value of all the equation parameters, a comparison is made between lasing wavelengths as predicted by the equation and as experimentally determined using laser-induced impedance changes to detect spectral lines in hollow cathode lamps. Agreement is found to be better than ±0.05 Å for all spectral lines used, with 68% of the predicted wavelengths within ±0.02 Å of their actual values. The micrometer drive for the birefringent filter, used in the CMX-4 to select an etalon order, is also calibrated using a quadratic polynominal equation, which gives predictions better than ±0.25 Å for all wavelengths tried in the regions of 5890 Å to 6050 Å and 6350 Å to 6720 Å, corresponding to the dyes R6G and R640, respectively.
Concerning the Application of FT-IR to the Study of Coal: A Critical Assessment of Band Assignments and the Application of Spectral Analysis Programs
Authors: Painter Paul C. , Snyder Randy W. , Starsinic Michael , Coleman Michael M. , Kuehn Deborah W. , Davis Alan
Published: August 2005

The problems associated with the application of FT-IR to the characterization of coal structure are critically discussed. The controversies concerning band assignments are considered and it is concluded that the strong 1600 cm−1 band can be assigned to an aromatic ring stretching mode that in most coals is intensity enhanced by the presence of phenolic groups. The application of computer routines to the determination of OH and CH groups is considered. Established criteria for curve fitting are applied to the problem. Qualitative identification of functional groups is achieved, but consistent quantitative measurements will require a determination of the relationship between the extinction coefficients of resolved bands.
Tertiary Interferograms in Fourier Transform Spectroscopy
Authors: Baghdadi Aslan , Forman Richard A.
Published: August 2005

Multiple passes, both within a semiconductor specimen and between the specimen surface and the interferometer, give rise to a series of extraneous “tertiary” interferograms in a Fourier transform spectrophotometer. These tertiary interferograms can lead to a possible error on the order of 1% in the measurement of the impurity content of a silicon wafer. However, this effect can be eliminated by a straightforward manipulation of the interferogram prior to transformation.
Fourier Transform Infrared Spectra of Calf Thymus DNA and its Reactions with the Anticancer Drug Cisplatin
Authors: Theophanides Theophile
Published: August 2005

Fourier transform infrared (FT-IR) spectra of deoxyribonucleic acid (DNA) and its reaction products with the anticancer drug cis-Pt(NH3)2Cl2, cis-diamminodichloroplatinum (abbreviated cisplatin) in water and heavy water solutions or gels have been obtained and studied. The mid-IR spectra show considerable changes in the carbonyl (C=0) region and weaker, but significant perturbations in the sugar-phosphate absorption region (PO2−, OPC and COP). The carbonyl bands at 1710 and 1686 cm−1 of the control DNA in H2O and D2O, respectively, disappear and shift to lower frequencies in the spectra of cisplatin + DNA with a r = Pt/P = 0.2. Furthermore, the sugar-phosphate band at 1054 cm−1 of the C—O stretching vibration of the ribose-phosphate bond is reduced in intensity and slightly shifted to higher frequencies, indicating a reorientation of the phosphate group. In addition, the P—O stretching vibration frequency at 970 cm−1 is reduced in intensity on interaction with the drug. These changes depend to some extent on the water content in the control DNA and in the cisplatin + DNA complex. The water molecules in DNA in the presence of cisplatin reorganize themselves. The attack of the platinum drug at the N7 site of the guanine molecule in DNA exerts an effect on the DNA structure through a modification of the water average configuration and its stabilizing effect on the secondary structure.
WCOT Capillary Column GC/FT-IR and GC/MS for Identifying Toxic Organic Pollutants
Authors: Shafer Kenneth H. , Cooke M. , DeRoos F. , Jakobsen R. J. , Rosario O. , Mulik J. D.
Published: August 2005

The combined data of high-resolution chromatography GC/FT-IR and GC/MS is used to identify a standard solution of priority pollutants. Identifications made by the individual library search routines are compared and an improvement is demonstrated in the number of identifications with the combined GC/FT-IR and GC/MS data. Both GC/FT-IR and GC/MS separations are performed on WCOT capillary columns. This provides the best separation possible and also permits fast and efficient comparison of spectral data when separations are performed on the same type of column. GC/FT-IR shows more selectivity for polar compounds, whereas GC/MS selectivity favors nonpolar compounds. These selectivity differences emphasize the complementary nature of (and the need for) both GC/FT-IR and GC/MS information.
Comparison of Three Instrumental Spectroscopic Techniques for Elemental Analysis of Kansas Shales
Authors: Amini Mohammad K. , Defreese James D. , Hathaway Lawrence R.
Published: August 2005

Four different Kansas shales, varying in coloration from a black (reduced) to a red (oxidized), were analyzed for several metal concentrations by flame atomic emission (FAE), flame atomic absorption (FAA), and inductively coupled plasma atomic emission (ICP). Shale samples analyzed by FAE and FAA were subjected to pretreatments including addition of releasing agents and extraction techniques because, as expected, measurements of trace metal concentrations without pretreatment resulted in significant errors. Chemical interferences in the analysis of shales by atomic spectroscopic techniques are severe due to high concentrations of Si, Al, Ca, Mg, and Fe. Organic matter, the presence of S and P, and enrichment in various minor and trace element species may also complicate the analysis of shales derived from reducing environments. However, flame results for pretreated samples show good agreement with ICP determinations on untreated samples. Among the shales investigated, those having higher organic content (black) were found to have higher concentrations of certain metals such as Cr, V, Zn, Cu, Ni, Pb, Mo, and Hg. This is related to the capability of the organic fractions of these shales to concentrate metals.
The Simultaneous Determination of Thorium, Niobium, Lead, and Zinc by Photon-Induced X-ray Fluorescence of Lateritic Material
Authors: Labrecque J. J. , Adames D. , Parker W. C.
Published: August 2005

A rapid method is presented for the simultaneous determinations of thorium, niobium, lead, and zinc in lateritic material from Cerro Impacto, Estado Bolívar, Venezuela. This technique uses a PDP—11/05 processor—based photon induced x-ray fluorescence system. The total variations of approximately 5% for concentrations of approximately 1 and 10% for concentrations of approximately 0.1% were obtained with only 500 s of fluorescent time. The values obtained by this method were in agreement with values measured by conventional flame atomic absorption spectroscopy for lead and zinc. The values for thorium measured were in agreement with the reported values for the reference materials supplied by NBL.
Molecular Orientation Measurements in Polymers by Infrared Spectral Subtraction
Authors: Garton A. , Carlsson D. J. , Wiles D. M.
Published: August 2005

The data manipulation ability of a Fourier transform IR spectrometer is exploited to characterize molecular orientation in polymers. In particular, the application of spectral subtraction to dichroic ratio determination and to the measurement of three-dimensional orientation via sample tilting and internal reflection spectroscopy is explored for nylon film samples.
Evaluation of Silicon-Chemiluminescence Monitoring as a Novel Method for Atomic Fluorine Determination and End Point Detection in Plasma Etch Systems
Authors: Zijlstra P. A. , Beenakker C. I. M.
Published: August 2005

Optical methods for the detection of atomic fluorine in plasma etch systems are discussed and an experimental comparison is made between detection by optical emission and by a novel method based on the chemiluminescence from solid silicon in the presence of atomic fluorine. Although both methods are, in principle, subject to interferences, they can readily be used for plasma etch process optimization and for end point detection.
Nature of the Carbonyl Stretching Modes in α-Dicarbonyl Compounds—The Pyruvate Series
Authors: Katon J. E. , Ray W. J.
Published: August 2005

The infrared and Raman spectra in the carbonyl stretching region have been recorded for a number of molecules of the pyruvate series. The data are compared with previously published data for the oxalate series. Analysis of these spectra indicates that there is little or no electronic interaction between the two unsaturated centers. It is therefore concluded that each carbonyl stretching mode in the infrared spectra of the pyruvate series reflects its own particular functionality.
Application of a Wavelength Modulation Inductively Coupled Plasma-Echelle Spectrometer to Cd and Pb Determinations in Marine Samples
Authors: McLaren J. W. , Berman S. S.
Published: August 2005

The installation and performance of a wavelength modulation system in a custom-built inductively coupled plasma-echelle spectrometer is described. The system, based on a computer-controlled rotatable quartz plate mounted just behind the entrance slit, permits extremely reproducible short (∼0.1 nm) wavelength scans in the vicinity of any chosen wavelength, as well as automatic two-point background subtraction during analyses. Its effectiveness, both in facilitating the characterization of spectroscopic interferences and in enabling accurate background correction, is demonstrated by determinations of trace quantities of cadmium and lead in biological tissues and sediments. Its potential use for wavelength modulation plasma emission spectrometry is discussed.
A Critical Comparison of Ar and Ar-N2 Inductively Coupled Plasmas as Excitation Sources for Atomic Emission Spectrometry
Authors: Montaser Akbar , Fassel V. A. , Zalewski J.
Published: August 2005

Ar-N2 plasmas generated by introducing N2 into the outer and the aerosol carrier gas flows were investigated using a 5 kW, 27.12 MHz crystal-controlled rf generator. The dependence of plasma geometry, plasma background intensity, net analyte emission intensity, signal/background ratio, signal/noise ratios, and the detection limits on forward power (1000 to 4000 W), the outer gas flow (15 to 50 liters/min) and aerosol carrier gas flow (1 to 2.5 liters/min), sample uptake rate (1 to 5 ml/min), and gas composition (0 to 100% N2) were studied for observation heights of 5 to 40 mm. Measurements were conducted simultaneously for 20 ion and neutral atom spectral lines. Ultrasonic nebulization, with aerosol desolvation, was employed. Except for the observation height, which was 10 mm, the optimum conditions for Ar-N2 plasmas containing 5 to 15% N2 in the outer gas flow were roughly identical to those of a conventional Ar plasma. When pure N2 was used in the outer flow, two sets of optimum conditions, quite different than the optimum conditions for the conventional Ar plasma, were found for the high and medium excitation energy lines. Detection limits and signal/background ratios of ion and neutral atom lines of the high excitation energies, excited in a pure Ar plasma, were superior to the results obtained in the Ar-N2 plasma when pure N2 was used in the outer flow. The opposite trend was observed for neutral atom lines of medium excitation energies. The use of N2 aerosol carrier gas, when the outer gas flow was pure Ar, deteriorated the detection limits of all elements.
Fourier Self-Deconvolution: A Method for Resolving Intrinsically Overlapped Bands
Authors: Kauppinen Jyrki K. , Moffatt Douglas J. , Mantsch Henry H. , Cameron David G.
Published: August 2005

The general theory of Fourier self-deconvolution, i.e., spectral deconvolution using Fourier transforms and the intrinsic lineshape, is developed. The method provides a way of computationally resolving overlapped lines that can not be instrumentally resolved due to their intrinsic linewidth. Examples of the application of the technique to synthetic and experimental infrared spectra are presented, and potential applications are discussed. It is shown that lines in spectra having moderate signal/noise ratios (∼1000) can readily be reduced in width by a factor of 3. The method is applicable to a variety of spectroscopic techniques.
Experimental and Theoretical Comparison of the Precision of Flame Atomic Absorption, Fluorescence, and Emission Measurements
Authors: Bower N. W. , Ingle J. D.
Published: August 2005

Theoretical equations and experimental evaluation procedures for the determination of the precision of flame atomic absorption, emission, and fluorescence measurements are presented. These procedures and noise power spectra are used to evaluate the precision and noise characteristics of atomic copper measurements with all three techniques under the same experimental conditions in an H2-air flame. At the detection limit, emission and fluorescence measurements are limited by background emission shot and flicker noise whereas absorption measurements are limited by flame transmission lamp flicker noise. Analyte flicker noise limits precision at higher analyte concentrations for all three techniques. Fluctutations in self-absorption and the inner filter effect are shown to contribute to the noise in atomic emission and fluorescence measurements.
Preparation of Standards for Thin Film Thickness Measurements by Energy Dispersive X-ray Analysis
Authors: Kammlott G. W.
Published: August 2005

Thin film measurements by energy dispersive x-ray analysis require appropriate standards. A method for preparing such standards by deposition of thin films and direct measurements of their thickness with a scanning electron microscope is described. These standards have been used to measure thickness of corrosion layers to within ±8.0 nm accuracy.
Closed-Form Calculation of Coherent Anti-Stokes Raman and Stimulated Raman Scattering Spectral Profiles
Authors: Perkins P. E. , Lewis J. W. L.
Published: August 2005

The third-order susceptibility is expressed as a summation of interfering resonant terms, each involving the phenomenological linewidth of the transition. Correlations of the finite linewidth of the laser sources with |χ(3)|2 (coherent anti-Stokes Raman spectroscopy) and –χ” (stimulated Raman scattering) are performed and closed-form expressions for the theoretical profiles are obtained.
Survey of Computer Aided Methods for Mass Spectral Interpretation
Authors: Martinsen David P.
Published: August 2005

Recent studies in the application of computerized techniques to mass spectral interpretation have been reviewed. The techniques have been divided into library search, pattern recognition, and interpretive methods. The more common methods in use in each category, as well as the more recent methods, are discussed. Earlier review articles are referenced for a more comprehensive treatment of earlier methods. The status of the large libraries of electron impact mass spectra is discussed and a number of attempts at improving the quality of those libraries are detailed.
Measurement of Solvent Shifts by Raman Difference Spectroscopy
Authors: Laane Jaan , Kiefer Wolfgang
Published: August 2005

The application of Raman difference spectroscopy for the determination of the small frequency shifts arising from solvent effects has been demonstrated. Data are presented for benzene-carbon disulfide, benzene-pyridine, and acetone-chloroform mixtures. The majority of the solvent shifts measured are less than 1.0 cm−1 and these can generally be determined with better than 10% accuracy using a rotating two-compartment liquid cell. The smallest shift measured in this work was 0.06 cm−1. While statistical analysis indicates that uncertainties as small as ±0.01 cm−1 can be obtained in many cases, artifacts may cause apparent shifts up to ±0.03 cm−1.
Ionization of Group II a Elements in the Direct Current Plasma: Effects of Ionization Potential on Emission Profiles
Authors: Williams Ronald R. , Coleman Geoffrey N.
Published: August 2005

Studies of background corrected ion and atom emission profiles of the group IIA elements in the two-electrode direct current plasma show great variation in both vertical and horizontal emission zones. Additionally, an anodic shift of the ion zone with respect to the atom zone is observed for the elements Be, Ca, and Mg, while Sr shows the reverse. Attempts to explain these spatial distributions using mechanisms proposed for the inductively coupled plasma have failed to adequately account for the observed results.
Atom transfer radical polymerization of sodium2‐acrylamido‐2‐methylpropanesulfonate
Authors: Masci Giancarlo , Giacomelli Laura , Crescenzi Vittorio
Published: August 2005

The first example of well‐controlled atom transfer radical polymerization (ATRP) of a permanently charged anionic acrylamide monomer is reported. ATRP of sodium 2‐acrylamido‐2‐methylpropanesulfonate (NaAMPS) was achieved with ethyl 2‐chloropropionate (ECP) as an initiator and the CuCl/CuCl2/tris(2‐dimethylaminoethyl)amine (Me6TREN) catalytic system. The polymerizations were carried out in 50:50 (v/v) N,N‐dimethylformamide (DMF)/water mixtures at 20 °C. Linear first‐order kinetic plots up to a 92% conversion for a target degree of polymerization of 50 were obtained with [ECP]/[CuCl]/[CuCl2]/[Me6TREN] = 1:1:1:2 and [AMPS] = 1 M. The molecular weight increased linearly with the conversion in good agreement with the theoretical values, and the polydispersities decreased with increasing conversion, reaching a lower limit of 1.11. The living character of the polymerization was confirmed by chain‐extension experiments. Block copolymers with N,N‐dimethylacrylamide and N‐isopropylacrylamide were also prepared. The use of a DMF/water mixed solvent should make possible the synthesis of new amphiphilic ionic block copolymers without the use of protecting group chemistry. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 4446–4454, 2005