bluuebunny/crossref_metadata_2025 huggingface dataset:
Detection of Spectral Overlap Interference in ICP-AES with an Empirical Linewidth Ratio Technique
Authors: Farwell S. O. , Kagel C. T.
Published: July 2005

ICP-AES line intensity data were fitted to a minimum-curvature smooth curve generated with the aid of a cubic semispline algorithm. These spline-fitted curves were used to obtain linewidth ratios which can provide accurate indication of spectral overlap with the use of only sample and standard spectra.
Some Practical Aspects of FT-IR/PBDS Part I: Vibrational Noise
Authors: Low M. J. D.
Published: July 2005

FT-IR photothermal beam deflection (PBD) signals are several orders of magnitude smaller than PBD signals generated in other spectral regions and by other means, so that vibrational rather than electronic noise is important to the production of FT-IR/PBD spectra at present. The interferometer of the PBD spectrometer produces mechanical vibrations, but the most serious disturbances arise in the environment and are of unknown origin and uncontrollable. The mechanical vibrations imposed on the optics lead to random, broad-band noise which can be decreased by multiple scanning, as well as to noise at discrete frequencies which can be nonrandom and consequently not be diminished by multiple scanning. Some types of such noise and their effects are described and discussed.
Quantitative Photoacoustic Spectroscopy: Determination of Fluorescein and Bromocresol Green Adsorbed on Modified Silica Gel Samples
Authors: Field R. S. , Leyden D. E. , Murthy R. S. Shreedhara
Published: July 2005

A series of standards was prepared by mixing the fluorescein or bromocresol green adsorbed on silica gel modified with N,N-diethylaminopro-pyltriethoxysilane with varying amounts of unmodified silica. Photoacoustic magnitude and phase values were obtained at their respective absorption maxima, 470 and 600 nm. Calibration graphs were prepared by combining the magnitude and phase into the response function. Two-component samples were prepared by mixing the different ratios of the standard samples. The concentration of the dyes in the two-component samples was determined by referring to the respective calibration graphs and solving a pair of simultaneous equations. The relative error in the determination ranged from −5.6% to 5.1% for fluorescein and −16.8% to 38% for bromocresol green when compared to their concentration determined by spectrophotometry.
Application of Photon Correlation and Multichannel Analysis Techniques to the Measurement of a Two-Line Spectrum: Simultaneous Determination of All Parameters
Authors: González F. , Cagigal M. P. , Rebolledo M. A.
Published: July 2005

In this paper the analysis of two spectral lines by using a digital correlator or a digital multichannel analyzer is studied by means of experiment and a computer simulation method. The errors involved in the simultaneous determination of the width, separation, and relative height of the lines are studied and compared.
Oxidized Nickel-Iron and the Effect of Absorption Modes on Infrared Emission
Authors: Zanzucchi P. J. , Yim M. W.
Published: July 2005

Metal oxide coatings are used on the surface of electronic components to improve heat dissipation through emission of infrared radiation. The physical properties of these films, e.g., composition and thickness, affect the spectral distribution of the emission. In addition, in the spectral region of the characteristic oxide vibrational modes, infrared emission is substantially reduced. In this paper, the infrared emissions for oxides on iron and Invar (36% Ni-Fe alloy) are compared. These metals are used in TV manufacture (shadow mask), and their oxide film properties are important to the operation of TV kinescopes.
Characteristic Infrared Absorption Frequencies of the Enol Group of 1,3-Dicarbonyl Compounds
Authors: Schiering David W. , Katon J. E.
Published: July 2005

Infrared spectra of several 1,3-dicarbonyl compounds from different organic chemical clauses have been recorded. Assignments of characteristic enol frequencies have been made, and group frequency ranges developed. In most cases, the ranges are reasonably narrow considering the great changes in overall structure of the examples studied. The enol structure affects to a significant degree the absorption frequencies of certain modes.
Spectral Properties of Sulfated Limestone and Marble: Implications for In Situ Assessment of Atmospheric Pollution Damage to Carbonate Rock Building Materials
Authors: Eastes John W. , Salisbury John W.
Published: July 2005

Infrared spectral reflectance of Salem Limestone and Shelborne Marble exposed to simplified artificial weathering by dilute sulfuric acid solutions is studied as a function of the concentration of surficial gypsum formed. Data presented indicate that calibration curves relating gypsum concentration to reflectance band strengths at 1.93, 6.5, and 8.5 μm can be constructed for both limestone and marble and that nondestructive quantitative compositional analysis is possible using either near-infrared (NIR) or mid-infrared (MIR) measurements. The preferred spectral region depends on the nature of the carbonate material under attack and the amount of gypsum formed. Detection limits for gypsum established for both the limestone and the marble indicate these spectroscopic techniques could provide a viable tool for early monitoring of the effects of certain atmospheric pollutants on carbonate rock building materials.
Morphological Investigation of Solute Particles Trapped from an Air-Acetylene Flame
Authors: Childers A. G. , Hieftje G. M.
Published: July 2005

A uniform-droplet generator has been employed to produce individual desolvated KCl particles in a laminar air-acetylene flame. The resulting particles were collected on various surfaces and at different points in their vaporization history. Morphological studies were then conducted on the trapped particles in order to better characterize the structural changes which occur during desolvation and vaporization. Particles collected early in their vaporization exhibited strong crystalline structure characteristic of KCl, whereas particles gathered later in their volatilization history showed evidence of fusion and, in some cases, the formation of hollow spheres. In addition to the morphological studies, the various collection surfaces and the collection technique itself were assessed. Direct collection on scanning-electron microscopy specimen stubs was judged to be best.
Comparison of Responses of 13C NMR and NIR Diffuse Reflectance Spectroscopies to Changes in Particle Size and Order in Cellulose
Authors: Himmelsbach D. S. , Barton F. E. , Akin D. E.
Published: July 2005

High-resolution solid-state 13C NMR and NIR diffuse reflectance spectra were obtained on microcrystalline and “noncrystalline” celluloses. Particle sizes and relative crystallinity were confirmed by scanning electron microscopy and MIR transmission spectroscopy, respectively. The results showed that NMR is more sensitive to order changes and less sensitive to particle size. NIR reflectance, on the other hand, is very sensitive to particle size changes and essentially insensitive to differences in order.
FT-IR Photoacoustic Spectra of Gaseous Group VIB Metal Chalcocarbonyl Complexes
Authors: Xu Zhen H. , Butler Ian S. , St.-Germain Francois G. T.
Published: July 2005

Attempts to record the room-temperature, FT-IR photoacoustic (PA) spectra of the crystalline group VIB metal chalcocarbonyls, M(CO)6 (M = Cr, Mo, W) and Cr(CO)5(CS), suprisingly failed owing to the high volatilities of the solid complexes in the PA cell, and excellent-quality gas-phase spectra were obtained instead. Vibrational assignments are proposed for these gases for the CO stretching and MCO bending fundamentals, and the associated binary overtone and combination spectra in the 4500–500 cm−1 region. The binary overtone and combination spectra are easily observed in the FT-IR/PA spectra and are useful in distinguishing between the four metal chalcocarbonyl complexes.
Ion Kinetic Energies in Inductively Coupled Plasma/Mass Spectrometry (ICP-MS)
Authors: Fulford J. E. , Douglas D. J.
Published: July 2005

Ion kinetic energies in an inductively coupled plasma/mass spectrometer (ICP-MS) system have been measured with the use of a retarding potential on the analyzing quadrupole. The energies differ markedly from those previously reported in the literature. This is attributed to the elimination of any arcing of the ICP to the sampling orifice or skimmer of the ICP-MS system. In the absence of secondary discharge effects, the ion energies increase with the mass of the ion and are consistent with those expected from molecular beam sampling from a plasma with a temperature of ∼5000 K and a potential of ∼2 V. Ion energies are found to be virtually independent of aerosol gas flow, plasma power, and sample matrix composition, allowing independent optimization of plasma parameters and ion optics.
New Quantitative Technique for Attenuated Total Reflection (ATR) Spectrophotometry; Calibration of the “CIRCLE” ATR Device in the Infrared
Authors: Sperline R. P. , Muralidharan S. , Freiser H.
Published: July 2005

A general method for spectroscopic determination of the incidence angle and number of reflections in ATR devices is described. This technique extends the inherent advantages of ATR by simplifying general quantitative spectroscopic measurements. Effects of polarization, beam focusing, errors of alignment, indices of refraction, handling of the optical elements, and surface activity of internal standard are discussed. Measured ATR absorbances are fitted mathematically with the use of incidence angle as a parameter. A standardizing solution, molar absorptivities for that solution, and knowledge of the dimensions of the internal reflection optical element are required. Application of the method to a cylindrical internal reflection (CIR) device gives the averaged incidence angle in the CIR with greater accuracy than is otherwise obtainable. With the use of a side-focusing Fourier transform spectrophotometer, the average incidence angle in the Spectra-Tech, Inc. “Micro-cell” “CIRCLE” CIR was 49.68 degrees ± 0.78%, and the number of solution-sensing internal reflections was 7.52 ± 1.95%.
A Critical Evaluation of Three Types of Diffuse Reflectance Infrared Accessories
Authors: Yang Paul W. , Mantsch Henry H. , Baudais Fred
Published: July 2005

Three geometrically different diffuse reflectance accessories were compared in terms of the throughput and ease of operation. The capability to discriminate the specular component against the diffuse reflectance component was investigated by the use of high refractive index samples. It was found that in all three accessories the specular as well as the diffuse reflectance components have similar reflection and polarization characteristics and that the specular component is primarily sample-dependent rather than accessory-dependent.
A Comparative Study of Two Computerized Spectrophotometers for the Near-Infrared Analysis of Wheat for Protein
Authors: Williams P. C. , Krischenko V. P.
Published: July 2005

Samples of hard red spring (HRS) wheat were compared on two computerized spectrophotometers of the same type, the Model 6350 Research Composition Analyzer. One of the instruments was located at the All Union Institute for Agrochemical Services, Moscow, U.S.S.R., the other at the Grain Research Laboratory, Winnipeg, Canada. Spectra, and analytical accuracy and precision, were compared on the two systems. While bands from the Moscow instrument appeared slightly sharper than its Winnipeg counterpart, log 1/ R signals from the two instruments were highly correlated for individual samples at all wavelengths studied, and absorption bands for individual samples occurred at essentially the same wavelengths. Several wavelengths selected for calibration were common to both instruments, and calibrations were developed on both, which enabled accurate analysis of HRS wheat for protein. Calibration constants differed for individual calibrations.
Fourier Transform Infrared Reflection Spectroscopy Studies of Organic Films Formed on Inorganic Substrates
Authors: Udagawa A. , Matsui T. , Tanaka S.
Published: July 2005

Reflection absorption spectroscopy on metal surfaces has been applied to reflection spectroscopy on nonmetallic inorganic materials with Fourier transform infrared spectroscopy. The optimal measurement conditions—polarization of incident light and angle of incidence—are discussed on the basis of a calculation using a model of a three-phase system consisting of air, an organic film, and an inorganic substrate. Reflection spectra of stearic acid films on glass substrates were obtained for both perpendicular and parallel polarized incident lights. The optimal measurement condition was for perpendicular polarization, at angle of incidence of 70°, although the signal-to-noise ratio (S/N) of reflection spectra under this condition was ten times less than the S/N of reflection absorption spectra. Reflection spectra on indium tin oxide substrates were obtained for only parallel polarized incident light, and the optimal angle of incidence was 73°. These results were in good agreement with the calculation results.
Room-Temperature Luminescence of Several Compounds on an α-Cyclodextrin-NaCl Mixture
Authors: Bello J. , Hurtubise R. J.
Published: July 2005

Fifty-five organic compounds of various sizes and functionalities were investigated for solid-surface room-temperature fluorescence (RTF) and phosphorescence (RTP) on an 80% α-cyclodextrin-NaCl matrix. Forty-two of these compounds showed either RTP and/or RTF on this matrix. The relative RTP intensities of the compounds were compared, and the results showed that triphenylene gave the strongest RTP signal, while phenanthridine gave the weakest signal. The range of the RTP limit of detection of the phosphorescent compounds on an 80% α-cyclodextrin-NaCl mixture was determined to be between 0.2 ng and 15 ng. The results showed the general analytical potential of this approach because of the large number of compounds yielding luminescence signals and the selectivity and sensitivity achieved.
A Flashback-Resistant Burner for Combustion Diagnostics and Analytical Spectrometry
Authors: Krupa R. J. , Culbreth T. F. , Smith B. W. , Winefordner J. D.
Published: July 2005

A general utility burner for the production of laminar, homogenous diffusion flames, which is immune to flashbacks, is presented. Because the fuel and oxidant mix on the surface of the burner rather than within the spray chamber, the flames cannot flashback. A wide variety of gas mixtures has been investigated, including oxygen, nitrous oxide, and nitric oxide as the oxidants. Any combination of fuel and oxidant can be safely burned to produced a stable, laminar, and audibly quiet flame. Flame temperatures can be varied over a wide range either by changing the fuel-oxidant ratio or by diluting the flame gases with an inert gas. In this manner, the optimum flame temperature and composition can be achieved. These burners are of general use in analytical emission, fluorescence, and photoacoustic spectrometry, as well as combustion diagnostics.
Spectral Characteristics of a New Spectrometer Design for Atomic Emission Spectroscopy
Authors: Karanassios V. , Horlick G.
Published: July 2005

Recently a new commercial spectrometer has been developed that combines a linear photodiode array detector and an echelle spectrometer with a very unique dispersion/selection/recombination line selector. In this system, light from a source such as an ICP is first predispersed with the use of a low-resolution (0.5 M) concave grating polychromator. Desired narrow-wavelength regions are selected with the use of a slotted mask in the focal plane of this polychromator. The selected wavelengths transmitted by this mask are then recombined into a parallel quasi-white beam with the use of a concave mirror and a second grating. This collimated quasi-white beam is then directed to an echelle grating and the output spectrum from the echelle is finally focused on a linear photodiode array detector. The optical configuration and characteristics of this instrument will be presented along with spectra obtained with the use of an ICP source illustrating its spectral characteristics for atomic emission spectrometry.
Analytical Figures of Merit and Interelement Effects with Air and Nitrogen Microwave-Induced Plasmas
Authors: Urh John J. , Carnahan Jon W.
Published: July 2005

A microwave (2450 MHz)-induced plasma (MIP) with nitrogen nebulization and plasma gases was developed and compared with an air-MIP similar to that previously reported in our laboratories. These plasmas were maintained at 300 to 500 W of forward power and were stable with pneumatic nebulized aqueous solution introduction. In general, metals with high metal-oxygen bond strengths, high excitation energies, and low ionization potentials exhibited superior detection limits in the N2-MIP. Several elements with emission lines in N2 and N2+ spectral regions yielded better detection limits in the air plasma. The effects of high concentrations (2%) of calcium, potassium, sodium, and phosphate ions upon the analytical signal intensities were examined. During direct solution nebulization, the analytical signals of both plasmas exhibited significant but predictable interferences from metals of low ionization potential and plasma loading. Matrix effects were more significant in the N2-MIP.
Vibrational Assignments of the Epihalohydrins
Authors: Nyquist R. A. , Putzig C. L. , Skelly N. E.
Published: July 2005

Liquid-, solution-, solid-, and vapor-phase infrared spectral data have been recorded for the epihalohydrins. The IR data recorded of the various physical phases enables specific band assignment for both rotational isomers. The spatial configuration of the rotational isomer existing in the solid phase is different from the spatial configuration of the rotational isomer existing in the vapor phase, while both spatial configurations exist in the liquid phase or solution phase. Vibrational frequency assignments are aided by comparison with vibrational assignments for the 3-halopropynes and the 3-halopropenes. Raman data are also used in making the vibrational assignments for epichlorohydrin, epibromohydrin, and epiiodohydrin.
Spatial Mapping of Transient Atomic Concentrations Using Acousto-Optic Deflection
Authors: Huie Carmen W. , Yeung Edward S.
Published: July 2005

We report a new imaging system for obtaining spatially and temporally resolved atomic absorption profiles for transient events. This is based on an aconsto-optic beam deflector that scans the probe laser beam in one dimension repeatedly across the spatial region of interest. Scan rates of 10 µs durations essentially freeze the absorbing species in time to allow a spatial resolution of 0.06 cm over a 1.2 cm length. With the use of 2K of buffer memory and a digitization interval of 200 ns (12 bits), the time evolution can be followed up to a total of 400 µs. The capabilities are demonstrated in the study of atom formation in a laser-generated plume from a sodium tungstate surface.
Infrared Emission Spectroscopy Studies of Metal Oxide Catalysts
Authors: Jonson Bo , Rebenstorf Bernd , Larsson Ragnar , Primet Michel
Published: July 2005

The spectral changes of a series of metal oxides, resulting from their oxidation of toluene, were studied by infrared emission spectroscopy. Comparative investigations were carried out with a grating spectrophotometer and with an interferometric Fourier transform spectrophotometer. The latter was found to be superior in the present kind of experiments.
Computer-Assisted Spectroscopic Analysis Using Orthonormalized Reference Spectra. Part I: Application to Mixtures
Authors: Nyden Marc R.
Published: July 2005

A new method for the spectroscopic analysis of mixtures is presented. The method involves computing the projections of the mixture spectrum in the space spanned by an orthonormal reference library. The use of orthonormalized reference spectra results in a significant reduction in the amount of computation involved in the direct spectroscopic analysis of mixtures.
Comparison of Resolution Enhancement by Different Computer Techniques of the Chlorophyll Carbonyls
Authors: Chapados Camille , Béliveau Jean , Trudel Michel , Levesque Charles
Published: July 2005

Several computer enhancement techniques are compared for their ability to resolve overlapping infrared carbonyl bands of chlorophyll obtained in the solid state. These methods are: the band fit optimization technique, the second-derivative technique, the subtraction of a super-smooth spectrum technique, and the Fourier self-deconvolution technique. The advantages and disadvantages of each technique are compared. In order to extract the maximum information on the spectra, two techniques should be used. The best combination we found was to first use the Fourier self-deconvolution technique, which gives some information on the number and the position of the bands, and—with this information—to then use the band fit optimization technique, which gives the exact intensity, bandwidth, and band shape, as well as the integrated intensity of all the bands.
EDXRF Analysis of Straits Chinese Porcelains for Zirconium and Niobium Using a Cadmium-109 Source
Authors: Yap C. T.
Published: July 2005

An annular Cd-109 source was used to induce fluorescent X-rays from 37 pieces of Straits Chinese porcelain of which four were modern pieces and the rest were produced from the nineteenth century up to the Republic period (1912–1939). Experimental data show that for zirconium and niobium infinite thickness is reached for a thickness of about 1.5 mm. A plot of the intensity of the Kα1 line of Zr against that of Nb shows that all Ch'ing and Republic pieces cluster together and are quite distinct from the modern pieces, allowing easy nondestructive identification of modern fakes.
Vibrational Spectra, Force Constants, and Si-O Bond Character in Calcium Silicate Crystal Structure
Authors: Handke Miroslaw
Published: July 2005

Vibrational spectroscopic methods were used to study the Si-O bond character in silicates with different complex anions and crystal structures. The following calcium silicates were examined: Ca,(SiO5), γ-Ca2(SiO4), β-Ca2(SiO4), Ca3(Si2O7), Ca(SiO3), and Ca(Si3O3). The band assignments in IR and Raman spectra of these compounds have been deduced mainly from 28Si−30Si and 40Ca−44Ca isotopic shifts. The GF matrix method and molecular approximation for force constant calculations in silicate anions were used. The Si-O bond parameters (bond order, charge distribution, and bond ionicity, etc.) were obtained from calculated force constants. The nature of Si-O bonds with respect to complex anion and crystal structure will be discussed.
On Temperature Determination from Rotational Raman Line Intensities
Authors: Doppelbauer Josef , Leyendecker Günter
Published: July 2005

A theoretical investigation of temperature determination from the pure rotational Raman spectra of diatomic and linear molecules is performed. Calculations are presented on the suitable selection of the lines used to minimize the random error. The problem is formulated in terms of rotational characteristic temperatures. Our results show, for single-channel detection, that temperature determination from the intensity ratio of only two properly selected lines is superior to the evaluation of many lines. Optimum line pairs are calculated for the most widely used molecules, H2 and N2, in the temperature range 300 to 2000 K. The random errors to be expected in this temperature range are given in a form which allows estimates to be made for any particular experimental situation.
Comprehensive Interferometric Characterization of Red and Near-Infrared Emissions of C, H, N, O, F, Cl, Br, I, P, S, and Si in a 370-W Microwave-Induced Helium Plasma
Authors: Pivonka D. E. , Schleisman A. J. J. , Fateley W. G. , Fry R. C.
Published: July 2005

The red/near-infrared emission spectrum from a 370-W atmospheric pressure helium microwave-induced plasma (MIP) has been characterized for eleven nonmetals with a Fourier transform spectrometer and silicon photodiode detector. A comprehensive list of all observed lines and relative intensities has been tabulated for MIP-excited emissions of C, H, N, O, F, Cl, Br, I, P, S, Si, and the helium background in the diode detector region 15,750 to 8500 cm−1 (6349–11,764 Å). Many of these red/near-infrared lines (especially of phosphorus and silicon) are reported for the first time in an analytically useful plasma. Data for silicon and phosphorus are shown to fit known Grotrian diagrams. The data of this paper were used with corresponding known upper-state energies and transitions to construct a partial Grotrian diagram for helium plasma emissions of iodine.
1H NMR Spectral Simplification with Achiral and Chiral Lanthanide Shift Reagents. Part III:* Vinclozolin
Authors: Hatzis Alexander , Rothchild Robert
Published: July 2005

The 60 MHz 1H NMR spectra of racemic vinclozolin, 1, have been studied at 28° in CDCI3 solution with the achiral reagent tris(6,6,7,7,8,8,8-heptafluoro-2,2-dimethyl-3,5-octanedionato)europium(III), 2, and the chiral reagents tris[3-(trifluoromethylhydroxymethylene)- d-camphorato] europium(III), 3, and tris[3-(heptafluoropropylhydroxymethylene)- d-camphorato]europium(III), 4. Reagent 3 produced only small lanthanide-induced shifts and no observable enantiomeric shift differences, ΔΔδ, with 3:1 molar ratios as high as 1.40. In contrast, chiral reagent 4 produced substantial ΔΔδ for the proton, Hβ, at C-2 of the ethenyl group syn to the oxazolidinedione ring and smaller ΔΔδ for the anti proton, Hβ, at the above carbon and for the CH3. With a 4:1 molar ratio of 0.581, ΔΔδ of 7.0 Hz was seen for Hβ. A 4:1 ratio of about 0.41 should be optimum for optical purity determinations; as little as 5% of the minor enantiomer should be detectable.
Infrared Quantitative Analysis in the Fourier Domain: Processing Vector Representations
Authors: Brown Chris W. , Obremski Robert J. , Anderson Philip
Published: July 2005

The methodologies for forming orthogonal vector representations of transformed infrared spectra of pure components in multicomponent systems are developed. Either the Gram-Schmidt orthogonalization method or factor analysis can be used to generate the vector representations; both give equivalent results when one vector representation per component is generated. The results of processing data in the Fourier domain using both orthogonalization methods are compared with those obtained by processing in the spectral domain for the following three systems: (1) simulated spectra; (2) real spectra with dissimilar features; and (3) real spectra with very similar features. In all cases, processing in the Fourier domain produces the optimum results while requiring a minimum amount of operator contributions.
Characterization of Near-Infrared Nonmetal Atomic Emission from an Atmospheric Helium Microwave-Induced Plasma Using a Fourier Transform Spectrophotometer
Authors: Hubert Joseph , Van Tra Huu , Tran Khanh Chi , Baudais Frederick L.
Published: July 2005

A new approach for using Fourier transform spectroscopy (FTS) for the detection of atomic emission from an atmospheric helium plasma has been developed and the results obtained are described. Among the different types of plasma source available, the atmospheric pressure microwave helium plasma appears to be an efficient excitation source for the determination of nonmetal species. The more complete microwave plasma emission spectra of Cl, Br, I, S, O, P, C, N, and He in the near-infrared region were obtained and their corrected relative emission intensities are reported. This makes qualitative identification simple, and aids in the quantitative analysis of atomic species. The accuracy of the emission wavelengths obtained with the Fourier transform spectrophotometer was excellent and the resolution provided by the FTS allowed certain adjacent emission lines to be resolved. These atomic emission lines were found to be adequate for analytical applications.
Signal-to-Noise Ratio Characteristics of an Inductively Coupled Plasma/Fourier Transform Spectrometer
Authors: Marra S. , Horlick G.
Published: July 2005

Inductively coupled plasma/Fourier transform spectroscopy (ICP-FTS) has the potential to become an excellent combined technique for analytical atomic emission spectrometry. However, the noise performance and behavior of a Fourier transform spectrometer for the measurement of atomic emission spectra in the ultraviolet spectral region is not well understood or characterized. In this study the noise behavior of ICP-FTS is empirically evaluated. The key empirical measurement carried out is the evaluation of complete standard deviation and signal-to-noise ratio spectra (i.e., those parameters measured as a function of wavenumber). A study of these spectra, along with the corresponding emission spectra as a function of concentration and matrix, allows an assessment of noise distribution, multiplex advantage/disadvantage, the nature of the limiting noise, detection limits, and precision.
Spectroscopic Temperature Determinations for a Microwave-Induced Helium Plasma Formed in a Laminar Flow Torch
Authors: Workman John M. , Brown Peter G. , Miller David C. , Seliskar C. J. , Caruso Joseph A.
Published: July 2005

This study represents the first plasma diagnostic investigation of a laminar flow torch configuration for microwave-induced plasma emission spectroscopy. Spatial intensity profiles indicate that this torch design facilitates the formation of a stable plasma discharge which does not reside on the walls of the plasma containment tube. Spectroscopic temperature determinations were based on the assumption of local thermodynamic equilibrium. Excitation temperatures were found to be several thousand degrees higher than those reported for other low-power He plasmas. Rotational temperature determinations afforded bimodal temperature distributions from the Boltzmann plots, with lower temperature slope regions comparable to values reported by others. Rotational temperatures derived from high-temperature slope regions were several thousand degrees above values obtained in other studies. Temperatures were evaluated as a function of radial position, microwave power, and flow rate.
Theoretical Analysis of the Crystalline Colloidal Array Filter
Authors: Spry Robert J. , Kosan David J.
Published: July 2005

The major parameters of a crystalline colloidal array optical filter have been investigated theoretically, and the results compared to published experimental data. This filter consists of an aqueous suspension of polystyrene spheres in a lattice which produces Bragg diffraction of incident light. The development of expressions for the filter bandwidth and attenuation utilized both dynamical x-ray diffraction theory and light scattering theory. The theoretical attenuation function indicates that extremely high absorbance values are achievable with relatively thin filters.
Determination of the Orientation of Adsorbed Pyridine and γ-MPS on Alumina Surface by Photoacoustic FT-IR Spectroscopy
Authors: Urban Marek W. , Koenig Jack L.
Published: July 2005

Fourier transform infrared photoacoustic spectroscopy has been applied to determine the structure and orientation of pyridine and γ-Metacryl-oxypropyltriethoxysilane (γ-MPS) on γ-Al2O3 surface. Adsorption of pyridine on activated γ-Al2O3 leads to formation of a pyridinium ion (pyN+-H) and pyridine N-oxide. The orientation of pyridinium ion on the alumina surface is random, whereas the pyridine N-oxide is parallel with respect to the surface. The adsorption of oligomers of γ-MPS gives parallel layers on the alumina surface. At low γ-MPS surface coverage, the carbonyl groups interact with the surface hydroxyl groups. Increasing surface coverage leads to an excess of the free C=O species.
Infrared Analysis of Particulates by FT-IR Emission/Transmission Spectroscopy
Authors: Solomon Peter R. , Carangelo Robert M. , Hamblen David G. , Best Philip E.
Published: July 2005

In this paper we report on a new method for the on-line chemical characterization of gas-suspended particulate and liquid droplet streams. The method is a combination of emission and transmission (E/T) spectroscopy performed using a Fourier transform infrared (FT-IR) spectrometer and a cell which allows analysis of room-temperature particulates surrounded by hot walls. The method was based on the discovery that the spectrum of radiation coming from such particles contained structure corresponding to the infrared absorption spectrum of the particulates. It was determined that the observed energy was wall radiation which reaches the detector after refraction by, and transmission through the particles. The shape of the observed spectrum relative to that of the wall spectrum is reduced at the absorption bands of the particulates. The general concepts of the E/T method were validated by samples with sizes varying from a few to several hundred microns with varying optical properties. For solids, excellent results were achieved for composition measurements. For a sample of known particle size, quantitative absorbance spectra were obtained from the E/T spectra with the use of a model based on ray optics. The spectra were in good quantitative agreement with absorbance spectra derived by the KBr pellet method for the same sample thickness. The E/T derived spectra were somewhat noisier than the KBr pellet spectra, but were free of Christiansen effect band distortions and scattering contributions. The E/T method has the additional advantage of requiring little or no sample preparation.
An FT-IR Study of the Water Absorbed in Kevlar-49® Fibers
Authors: Chatzi E. G. , Ishida H. , Koenig J. L.
Published: July 2005

Diffuse reflectance Fourier transform infrared spectroscopy has been used in order to detect absorbed water hydrogen-bonded to Kevlar-49® fibers. Varying amounts of KBr overlayers were used on the top of each sample in order to increase the surface selectivity of the technique. Three different O-H stretching vibrations of absorbed water were detected in the fibers exposed to saturated water-vapor atmosphere. Two peaks at 3640 and 3560 cm−1 are attributed to absorbed water that is weakly hydrogen-bonded to amide groups of the polymer. A broad absorption around 3450 cm−1 is characteristic of liquid-like water clustered in microvoids and other sites inside the fibers. The spectra of dried Kevlar-49® fibers show an unbonded amide N-H stretching peak at 3431 cm−1, indicative of regions with less perfect chain packing. At least part of these groups hydrogen-bond with absorbed water, depending on their availability.
Comparison of Transmission and Diffuse Reflectance Sampling Techniques for FT-IR Spectrometry of Silane-Modified Silica Gel
Authors: Blitz J. P. , Murthy R. S. Shreedhara , Leyden D. E.
Published: July 2005

Two sampling techniques are compared to study the effect of silylation reaction conditions on the extent of methoxy group hydrolysis of trimethoxymethylsilane (TMMS) on the Cab-O-Sil surface. When a pressed pellet of TMMS-modified Cab-O-Sil is used for transmission studies, the methoxy groups hydrolyze rapidly while the same sample studied by diffuse reflectance is stable toward hydrolysis for at least 60 min. The release of water from the silica gel pores when the sample is pressed is believed to be the reason for the rapid hydrolysis. To avoid undesirable hydrolysis of the silane, the diffuse reflectance sampling technique is preferred.
A Novel, In-Situ Method for Absolute Spectral Sensitivity Calibration of a Spectrometer-Detector System by Using Laser-Induced-Fluorescence Spectroscopy
Authors: Hirabayashi A. , Okuda S. , Nambu Y. , Fujimoto T.
Published: July 2005

We propose a calibration method for the absolute sensitivity of a spectrometer-detector system by applying laser-induced-fluorescence spectroscopy (LIFS) to a discharge plasma. The object of our experiment is to determine the absolute line intensity emitted from the plasma: For a spectral line, the absolute lower-level population on the tube axis before the laser excitation is determined by the self-absorption method combined with LIFS, which determines its spatial distribution, while the upper-level population is negligible compared with the lower-level population. When intense laser-excitation (broad-line excitation) saturates the upper-level population, its absolute value is given from the lower-level one as determined above. By combining the line intensity and the detector output, we determine the absolute sensitivity of the detection system. The above procedure has been applied to He(I) 504.8-nm and Ne(I) 616.4-nm transitions. The results are compared with our previous determination against a tungsten ribbon lamp.
A New Internal Reflection Element Design for High Optical Throughput in FT-IR
Authors: Messerschmidt Robert G.
Published: July 2005

A novel geometry for internal reflection elements is described. These elements have been found most useful in the FT-IR analysis of samples by attenuated total reflectance (ATR). Both single and multiple internal reflection elements are described. These elements provide three basic benefits. First, the geometry is such that an element may be exchanged for another of differing angle of incidence without the need for optical realignment of the sampling accessory. Second, for a given element thickness and width, the design allows a larger aperture over the conventional designs (parallelograms and trapezoids) for angles of incidence greater than 45 degrees, resulting in better sensitivity. Third, the elements are of a simple design, and are easy to fabricate.
A Photodiode Array Fourier Transform Spectrometer Based on a Birefringent Interferometer
Authors: Okamoto Takayuki , Kawata Satoshi , Minami Shigeo
Published: July 2005

A new version of the photodiode array Fourier transform spectrometer for visible spectroscopy is described. In this version, a birefringent interferometer with a Wollaston prism produces a spatial interferogram of the radiation, which is detected by a linear photodiode array. In addition to the merit of having no mechanical moving parts, this spectrometer has the beneficial advantage of the simple and rugged optical setup and alignment due to its common-path and in-line interferometer formation. These advantages lend this spectrometer to field-use applications. Emission spectra of a low-pressure mercury lamp and a light-emitting diode and an absorption spectrum of a didymium glass filter measured by the developed spectrometer are presented.
A High-Vacuum-Cell Approach to SERS Studies of Thin Films on Nonmetallic Surfaces
Authors: Parry D. B. , Dendramis A. L.
Published: July 2005

A high-vacuum cell designed for obtaining surface-enhanced Raman scattering (SERS) spectra of thin films on nonmetallic surfaces is described. The cell is shown to improve one's ability to obtain SERS spectra with acceptable S/N ratios and drastically reduced interference from sample alteration and/or bands typically assigned to graphitic carbon. This cell forms the basis of a pragmatic approach to obtaining SERS spectra from interfacial systems that applied surface scientists will likely be faced with in their work. We have applied this new sampling approach to the study of thin films of polystyrene, palmitic acid, and cetyltrimethylammonium bromide deposited on Si surfaces.
A New Technique for the Elimination of Fluorescence Interference in Raman Spectroscopy
Authors: Bright Frank V. , Hieftje Gary M.
Published: July 2005

A new instrument for Raman spectroscopy has been constructed with the use of a cw or mode-locked argon-ion laser as the excitation source and a microwave spectrum analyzer for discrimination between fluorescence and Raman scatter. To demonstrate the new instrument's capability, the weak Raman scatter of water was resolved from the intense fluorescence from rhodamine 6G. Theoretically predicted relative errors in the new procedure are calculated and experimental results are shown to be in good agreement with theory.
Advantages of Dual-Beam Interferometry in Fourier Transform Infrared Spectrometry
Authors: Beduhn Donald L. , White Robert L.
Published: July 2005

A dual-beam Fourier transform infrared spectrometer (FT-IR) is described. Sensitivity improvement, photometric accuracy, and instrument stability are evaluated by comparing dual-beam spectra with conventional single-beam spectra. Dual-beam FT-IR data acquisitions require an order of magnitude less measurement time than single-beam acquisitions for spectra of comparable signal-to-noise ratios. Application of dual-beam FT-IR for analysis of a highly transmitting sample is discussed. Single fiber analysis without masking and without an infrared microscope is described.
A Comparison of FT-IR/PA and FT-IR/PBD Spectra of Powders
Authors: Varlashkin P. G. , Low M. J. D. , Parodi G. A. , Morterra C.
Published: July 2005

FT-IR photoacoustic (PA) and also photothermal beam deflection (PBD) spectra were recorded with the same particulate samples (graphite, charcoal, aspirin, and silica) under the same conditions in order to compare the quality of the spectra obtainable with the two techniques. A PA cell fitted with windows for the PBD laser probe beam was used, and PA and PBD spectra of each sample were recorded at 8 cm−1 resolution at each of the four different interferometer scan velocities. Although the overall aspects of FT-IR/PA and FT-IR/PBD spectra are the same, the signal-to-noise ratios of PA spectra are appreciably better than those of PBD spectra because PBD detection is more prone to disturbance by vibration than is PA detection. Absorption bands appear at the same wavenumbers in PA and PBD spectra. However, the relative intensities of bands of PBD spectra depend on the absorptive properties of the powdered solids; with weak absorbers, some bands may not be detected at all. PAS can be used with all powders. PBDS is of little or no use for the examination of weakly absorbing powders unless they scatter IR radiation extensively.
The Chemical Interaction of Organic Materials with Metal Substrates. Part I: ESCA Studies of Organic Phosphate Films on Steel
Authors: Schuetzle D. , Carter R. O. , Shyu J. , Dickie R. A. , Holubka J. , McIntyre N. S.
Published: July 2005

ESCA and ellipsometry have been used to determine the film thickness, molecular orientation, and chemical bonding of an organic phosphate on polished steel substrates. The organic phosphate studied was formed as a reaction product of one mole of the diglycidyl ether of bis-phenol-A (DGEBA) with two moles of phosphoric acid, and comprised the mono- and diphosphate adducts of DGEBA. The steel substrates were found to bear an iron oxide layer that was 19 ± 4 Å in thickness as determined with the use of angle-resolved ESCA depth analysis. Ellipsometry measurements gave an iron oxide thickness of 26 ± 3 Å. Surface treatment of steel with the organic phosphate homogeneously covered the surface with 30 ± 5 Å of the coating as determined with the use of the ESCA depth analysis. The phosphate end-groups of the organic phosphate were concentrated at the coating/iron oxide interface. A shift in the phosphorus (2p) spectra from 135.2 to 134.2 eV was observed when the organic phosphate coating bonded to the iron oxide substrate. The binding energy of 134.2 eV was close to that observed for an iron organophosphate reference material at 134.0 eV. A shift in the iron (2p) spectra from 711.0 to 711.7 eV at a sampling depth of approximately 35 Å indicates the possible formation of an iron organic phosphate at the iron oxide/coating interface. The carbon and oxygen spectra confirmed the spatial orientation of the organic phosphate on the surface.
Nonlinear Effects of Digitizer Errors in FT-IR Spectroscopy
Authors: Baghdadi Aslan , Gladden Warren K. , Flach Donald R.
Published: July 2005

This paper is an investigation of the effects of errors in the analog-to-digital converter (ADC) of a Fourier transform infrared (FT-IR) spectrometer on the photometric accuracy of that spectrometer. The effect of ADC errors on the spectrum after Fourier transformation is calculated analytically for monochromatic, two-line, and wide square band emission spectra. Numerical modeling is used to extend the analysis to absorption spectra, and to include the effects of noise on the amplitude of absorbance bands. These analyses showed that ADC errors can generate artifacts throughout the spectrum, although the largest effects occur at sharp spectral features. Errors as large as 8% in the amplitude of absorbance bands can be produced by ADC errors of one least significant bit (LSB), in a 15-bit ADC. These results were confirmed qualitatively by measuring the net height of the oxygen vibrational band in silicon at 1107 cm−1 using four different ADC circuit boards in the same FT-IR spectrometer. At the highest signal levels, the ADCs disagreed by as much as 4%, even though their static transfer characteristics (which were measured in a separate experiment) exhibited errors of less than ±2 LSBs.
Draft Requirements for Molecular Spectroscopy Data Banks—A Discussion Document
Authors: Derendjaev B. G.
Published: July 2005

Computers are used in spectroscopy laboratories throughout the world. However, to avoid needless duplication of work and to maximize the potential of the vast mass of data now available, the stored information must be accessible to all; such data exchange can only be achieved by a certain degree of standardization, both in form, and in volume. As an aid to newcomers and to assist this international exchange of machine-readable data, the International Union of Pure and Applied Chemistry (IUPAC) Commission on Structure and Spectroscopy (1.5) intends to work out guidelines as to the form and volume of data representation in molecular spectroscopy banks.
A Portable Fiberoptic Monitor for Fluorimetric Bioassays
Authors: Vo-Dinh T. , Griffin G. D. , Ambrose K. R.
Published: July 2005

A simple and portable fiberoptic instrument for fluorimetric bioassays is described. The instrument is designed to be readily adaptable to commercially available biotesting wells on microplates. The microwells can also be used as interchangeable sensor heads. The utility of the fiberoptic biosensor is illustrated with a model enzyme-linked immunosorbent assay (ELISA) used to measure varying amounts of rabbit immunoglobulin G from 10 pg to 1 μg. The detection method utilizes an enzyme-amplified immunoassay of 4-methylumbelliferone phosphate as the enzyme substrate. The sensitivity of this assay is three orders of magnitude better than that obtained with a conventional ELISA absorption spectrometric assay using a commercially available reader.
Hadamard Transform Photothermal Deflection Imaging
Authors: Fotiou Fotios K. , Morris Michael D.
Published: July 2005

A 69-element Hadamard mask is used to encode a line-focused excimer laser beam to obtain spatially multiplexed photothermal deflection signals. The spatial distribution and relative quantities of potassium chromate samples on silica are recovered by Hadamard transformation.
An Improved Uniform-Size-Droplet Generator
Authors: Childers Alfred G. , Hieftje Gary M.
Published: July 2005

A new design is presented for a fixed-trajectory, uniform-size-droplet generator. This droplet generator is useful in a variety of scientific studies, one of which is of solute atomization in analytical flames. The improved droplet generator provides more stable droplet production, production of droplets over a wider range of sizes, and easier operation than earlier designs. Fabrication details are provided and performance of the new device is assessed.
A Multisurface Matrix-Isolation Apparatus
Authors: Hauge Robert H. , Fredin Leif , Kafafi Zakya H. , Margrave John L.
Published: July 2005

A multisurface matrix-isolation apparatus has been designed and interfaced to an FT-IR vacuum spectrometer. The design permits independent matrix-isolation studies with sixty different surfaces. It also allows direct measurement of matrix gas to guest ratios with an integral cooled quartz crystal microbalance. Problems associated with moving the matrix block while maintaining good thermal contact are discussed. Finally, some applications to studies of coal pyrolysis, metal atom chemistry, and quantitative analysis are presented.