Characterization of Crystalline Phases in Fly Ash by Microfocus Raman Spectroscopy

1984 ◽  
Vol 43 ◽  
Author(s):  
Barry E. Scheetz ◽  
William B. White
Keyword(s):  
Raman Spectroscopy ◽  
Fly Ash ◽  
Raman Spectra ◽  
Structural Information ◽  
Crystalline Phases ◽  
Individual Basis ◽  
Laser Raman ◽  
Raman Microprobe

AbstractThe laser Raman microprobe was used to interrogate individual fly ash particles as small as 1 μm diameter and record “fingerprint” Raman spectra from both crystalline and non-crystalline components.of the fly ash. When compared to reference patterns of known crystalline phases, the Raman spectra can be used to identify crystalline phases and can give some structural information on other phases. Furthermore, because this method characterizes fly ash particles on an individual basis, correlations to both color and morphology of the particles can be made.

Laser Raman Microprobe Characterization of Fly Ash

1985 ◽  
pp. 145-154
Author(s):  
Barry E. Scheetz ◽  
William B. White ◽  
F. Adar
Keyword(s):  
Fly Ash ◽  
Laser Raman ◽  
Raman Microprobe

Raman Spectral Characterization of Pure and Doped Fused Silica Optical Fibers

1975 ◽  
Vol 29 (4) ◽  
pp. 337-344 ◽  
Author(s):  
G. E. Walrafen ◽  
J. Stone
Keyword(s):  
Raman Spectroscopy ◽  
Raman Spectra ◽  
Optical Fibers ◽  
Fused Silica ◽  
Laser Raman ◽  
Laser Raman Spectra ◽  
Raman Spectral ◽  
Oh Content ◽  
Absorption Measurements

The utility of Raman spectroscopy as a means of characterizing the properties of pure and doped fused silica has been investigated. Laser-Raman spectra were obtained by forward scattering from solid optical fibers ∼35 to 85 m in length using 514.5 nm excitation with an “image slicer” and a Cary model 81 instrument. Clad and unclad fibers of fused silica and doped fibers having SiO2-GeO2 and SiO2-GeO2-B2O3 cores were examined. Raman spectra were also obtained from bulk samples of glasses, including pure GeO2, pure B2O3, and various compositions of SiO2-GeO2, SiO2-B2O3, and SiO2-GeO2-B2O3. The addition of dopants to fused silica was found to alter the Raman spectrum both by the appearance of new bands, roughly proportional to dopant concentration and not common either to the fused silica or to the dopant alone, and by the marked alteration of other Raman bands, which is indicative of changes in the local intermolecular order. Thus, addition of GeO2 produces new Raman bands at ∼675 and ∼1000 cm−1; and of B2O3, new bands at ∼940 and ∼1350 cm−1. Addition of GeO2 and/or B2O3 weakens the relatively sharp Raman lines near 485 and 600 cm−1 (and a similar but small effect was also noted with increasing OH content). GeO2 and B2O3 together also produce observable narrowing of the broad intense 440 cm−1 Raman contour. These spectral effects are interpreted, respectively, in terms of a decrease in the concentrations of [Formula: see text] and [Formula: see text] defects produced by dopant addition and of a concomitant reordering of the silica structure. Raman spectroscopy thus appears to be a useful optical technique for elucidating the properties of dopants that have been especially chosen for good optical transmission and hence are not easily detectable by absorption measurements.

The Analysis of Discrete Fine Particles by Raman Spectroscopy

1975 ◽  
Vol 29 (5) ◽  
pp. 396-404 ◽  
Author(s):  
G. J. Rosasco ◽  
E. S. Etz ◽  
W. A. Cassatt
Keyword(s):  
Raman Spectroscopy ◽  
Organic Compounds ◽  
Raman Spectra ◽  
Fine Particles ◽  
Chemical Characterization ◽  
Solid Particles ◽  
Laser Raman ◽  
Linear Dimensions ◽  
Conventional Laser

A conventional laser Raman spectrometer has been modified and used to obtain useful Raman spectra from discrete solid particles as small as 0.7 µm in linear dimensions. Spectra obtained from single, micrometer-sized particles of several inorganic and organic compounds are reported. Simplified calculations are discussed which provide an estimate of detectability levels and other problems associated with these measurements. Certain parameters that must be considered in the design of an instrument especially intended for use in the chemical characterization of single fine particles are reviewed in the light of this work.

Dimethylnitrosamine Detection and Measurement Using Laser Raman Spectroscopy

1977 ◽  
Vol 31 (6) ◽  
pp. 515-518 ◽  
Author(s):  
Dwaine M. Thomas
Keyword(s):  
Raman Spectroscopy ◽  
Raman Spectra ◽  
Laser Raman Spectroscopy ◽  
Laser Raman ◽  
Signal Response

The Raman spectra of various concentrations of dimethylnitrosamine in water have been measured. The lowest concentration detected was 10 mg/l. Instrumental parameters were varied to optimize the signal response.

Characterization of the coke formed on reforming catalysts by laser raman spectroscopy

1985 ◽  
Vol 16 (3) ◽  
pp. 343-354 ◽  
Author(s):  
D. Espinat ◽  
H. Dexpert ◽  
E. Freund ◽  
G. Martino ◽  
M. Couzi ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Laser Raman Spectroscopy ◽  
Laser Raman ◽  
Reforming Catalysts

Application of Laser-Excited Raman Spectroscopy to Organic Chemistry I. Raman Spectra of Some Acyclic Monoterpenes

1969 ◽  
Vol 23 (6) ◽  
pp. 610-615 ◽  
Author(s):  
Stanley K. Freeman ◽  
Dana W. Mayo
Keyword(s):  
Organic Chemistry ◽  
Raman Spectroscopy ◽  
Raman Spectra ◽  
Infrared Spectra ◽  
Double Bonds ◽  
Laser Raman ◽  
Laser Raman Spectra

Laser-Raman spectra of 12 acyclic terpenoids has been recorded. Assignments were made for stretching mode vibrations of carbon-carbon double bonds by comparison with infrared spectra. The results of intensity and depolarization studies are discussed.

Raman Addition Spectroscopy with a Rotating Cell

1975 ◽  
Vol 29 (5) ◽  
pp. 386-389 ◽  
Author(s):  
Arthur K. Covington ◽  
Jennifer M. Thain
Keyword(s):  
Raman Spectroscopy ◽  
Raman Spectra ◽  
Relative Intensity ◽  
Internal Standard ◽  
Laser Raman Spectroscopy ◽  
New Technique ◽  
Reference Substance ◽  
Laser Raman ◽  
Intensity Measurements ◽  
A New Technique

A new technique is described for obtaining quantitative relative intensity measurements, in the study of solution equilibria by laser-Raman spectroscopy, without the necessity for adding an internal standard to the sample. A rotating cylindrical double cell with separate compartments for sample and reference is used to superimpose the Raman spectra of sample and reference and hence avoid any uncertainties arising from the displacement of the equilibrium by reference substance addition.

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