The Influence of Slit-Width on the Shape and Intensity of Infra-Red Absorption Bands

1951 ◽  
Vol 4 (2) ◽  
pp. 172
Author(s):  
JB Willis
Keyword(s):  
Experimental Data ◽  
Half Width ◽  
Slit Width ◽  
Absorption Bands ◽  
Infra Red ◽  
Spectrometer Slit

Making certain assumptions as to the shape of infra-red absorption bands and the shape of the slit function of the monochromator, expressions are obtained for the dependence on spectrometer slit-width of the intensity and half-width of absorption bands. Experimental data to confirm the accuracy of these deductions are presented.

Microphotometric Errors for Photographically Recorded Spectral Lines of Nonuniform Half-Width

1978 ◽  
Vol 32 (5) ◽  
pp. 433-444 ◽  
Author(s):  
L. C. McGonagle ◽  
J. A. Holcombe
Keyword(s):  
Line Width ◽  
Half Width ◽  
Slit Width ◽  
Spectral Lines ◽  
Average Error ◽  
Spatially Resolved ◽  
Source Line ◽  
Line Widths ◽  
Spectrometer Slit ◽  
The Impact

Various microphotometric (or densitometric) techniques for generating quantitative intensity information from photographically recorded spectral lines of time or spatially resolved sources are discussed. The impact of various parameters on the accuracy of quantitative densitometry is presented. These parameters include line widths of the calibration spectrum, source line broadening, microphotometer scan slit width and the optical density of the photographic image. Nonrandom errors associated with the use of various microphotometer slit widths for spectral lines of nonuniform half-width are presented. Spectral lines which are uniform and exhibit slit width or diffraction limited resolution can be scanned with any size microphotometer slit width as long as the calibration curve is prepared using the same scan slit width. The use of microphotometer slit widths narrower than the line width produce H and D curves with maximal γ and increased accuracy in the final intensity value. A density-to-intensity conversion accuracy with a 6% average error was determined for SA-1 plates. For sources whose line widths are larger than the spectrometer bandpass, minimal errors are generated by using a narrow line source for calibration and scanning this spectrum with a slit width less than the line width. Scanning of the broadened line of interest is accomplished using a scan slit width equal to approximately twice the spectrometer slit width. Under these conditions an average error of approximately 11% was determined experimentally for SA-1 plates.

scholarly journals INFRARED ABSORPTION LINES IN BORON-DOPED SILICON

1963 ◽  
Vol 41 (11) ◽  
pp. 1801-1822 ◽  
Author(s):  
Konrad Colbow
Keyword(s):  
Experimental Data ◽  
Excited States ◽  
Ground State ◽  
Half Width ◽  
Stark Broadening ◽  
Boron Doped ◽  
Doped Silicon ◽  
Spectrometer Slit ◽  
Proper Allowance ◽  
Internal Strains

In boron-doped silicon, optical absorption takes place through the excitation of bound holes from the ground state to excited states. This leads to a line spectrum. Because of a lack of sufficient resolution and a failure to make proper allowance for line distortion by the finite spectrometer slit width, previous authors gave a misleading picture of the low-temperature half-width, the temperature dependence of this half-width, and the onset of concentration broadening at low temperatures.New experimental data are presented and explained by introducing the mechanism of statistical Stark broadening due to ionized impurities, and by modifying Baltensperger's (1953) theory for concentration broadening. At low impurity concentration the width is attributed to phonon broadening (Barrie and Nishikawa 1963) and internal strains (Kohn 1957).

The infra-red spectrum and molecular configuration of sodium deoxyribonucleate

1957 ◽  
Vol 239 (1219) ◽  
pp. 446-463 ◽  
Keyword(s):  
Relative Humidity ◽  
Vapour Phase ◽  
Molecular Configuration ◽  
Absorption Bands ◽  
Oriented Films ◽  
Infra Red ◽  
Modes Of Vibration ◽  
Water Measurement ◽  
Phosphate Groups ◽  
Polarized Radiation

The infra-red spectra of oriented films of sodium deoxyribonucleate have been investigated between 700 and 4000 cm -1 using polarized radiation and under varying degrees of relative humidity. Similar spectra have been obtained when the films have been deuterated by vapour-phase exchange with heavy water. It is found that the infra-red dichroism of nearly every band increases with the relative humidity. Many of the principal absorption bands can be assigned to separable modes of vibration in the bases, the phosphate groups or the absorbed water. Measurement of the dichroic ratios of certain of these bands indicates that at high relative humidity the bases must be nearly perpendicular to the orientation direction. The configuration deduced for the phosphate groups is unlike that proposed in the Crick-Watson model, but is in essential agreement with that recently proposed by Wilkins and his co-workers. Some observations are also reported on the corresponding spectra of sodium ribonucleate. Since no dichroism was observed, no conclusions can be drawn regarding the molecular configuration of this polymer.

Local Structure and Er3+ Emission from Pseudo-Amorphous GaN:Er Thin Films

1998 ◽  
Vol 536 ◽  
Author(s):  
S. B. Aldabergenova ◽  
M. Albrecht ◽  
A. A. Andreev ◽  
C. Inglefield ◽  
J. Viner ◽  
...  
Keyword(s):  
Thin Films ◽  
Room Temperature ◽  
Amorphous Matrix ◽  
Broad Band ◽  
Resonant Absorption ◽  
Absorption Bands ◽  
Host Matrix ◽  
Transmission Electron ◽  
Infra Red ◽  
Band Edge Luminescence

AbstractWe report on strong Er3+ luminescence in the visible and infra-red regions at room temperature in amorphous GaN:Er thin films prepared by DC magnetron co-sputtering. The intensity of the Er3+ luminescence at 1.535 μm corresponding to 4I13/2 → 4I15/2 transitions is greatly enhanced after annealing at 750°C. In this material GaN crystallites have formed and embedded in the continuous amorphous matrix. The crystallites are 4 to 7 nm in diameter as analyzed by high resolution transmission electron microscopy. The absorption edge, extending three orders of magnitude in absorption coefficient in the spectral range from 0.5 to 3.5 eV, is superimposed on resonant absorption bands of Er3+ ions.The total photoluminescence spectrum consists of welldefined Er3+ luminescence peaks imposed on a broad band edge luminescence from the amorphous GaN host matrix.

scholarly journals Forensic Examination of Inks Extracted from Printed Documents using Fourier Transform Infrared Spectroscopy

2018 ◽  
pp. 10-17
Author(s):  
Paul Ocheje Ameh ◽  
Musa Suud Ozovehe
Keyword(s):  
Fourier Transform ◽  
Infrared Spectroscopy ◽  
Fourier Transform Infrared Spectroscopy ◽  
Alkyd Resin ◽  
Epoxy Resins ◽  
Ftir Spectra ◽  
Absorption Bands ◽  
Triarylmethane Dyes ◽  
Infra Red ◽  
Aliphatic Ester

Yellow, cyan, magenta and black inks were extracted from documents printed using two common brands of printing cartridge in Nigerian market and analyzed to identify / compare the functional groups present using Fourier Transform Infra-red Spectroscopy (FTIR). The FTIR spectra obtained were found to show highly characteristic absorption bands depending on the composition of the printer inks. Also, the results indicated the presence of triarylmethane dyes, epoxy resins, alkyd resin and esters in all the inks as they are peaks assigned to the vibration of aliphatic ester, asymmetrical and symmetrical stretching. The pure ink and its extract from the same band were also found to exhibit similar FTIR spectra while inks extract from different brands exhibits marked difference in absorption bands. This research can provide valuable information if an admitted sample is provided for comparing with the suspect printed document.

scholarly journals Infrarotmessungen zur Ring-Ketten-Struktur des amorphen Selens

1972 ◽  
Vol 27 (8-9) ◽  
pp. 1246-1251 ◽  
Author(s):  
H. Gobrecht ◽  
G. Willers ◽  
D. Wobig ◽  
J. Zirre
Keyword(s):  
Amorphous Selenium ◽  
Absorption Bands ◽  
Additional Absorption ◽  
Ring Molecules ◽  
Polymeric Chains ◽  
Infra Red

Abstract The infra-red spectrum of red amorphous selenium has been studied in the region of 1 μm to 25 μm. The formation of Se8-ring molecules as well as polymeric chains Sen has been observed by investigating non-fundamental vibrations. Additional absorption bands at 7.85 μm (1274 cm-1), 8.95/9.35 μm (1117/1070 cm-1) and 12.35 μm (810 cm-1) are reported. They are assigned to multiphonon processes of the type E fundamental of Sen at 74.1 μm (135 cm-1).

Electron effective mass values in GaAsxSb1−x alloys

1981 ◽  
Vol 59 (7) ◽  
pp. 939-944 ◽  
Author(s):  
Paul Devlin ◽  
Hassan M. Heravi ◽  
John C. Woolley
Keyword(s):  
Experimental Data ◽  
Effective Mass ◽  
Conduction Band ◽  
Faraday Rotation ◽  
Room Temperature ◽  
Electron Effective Mass ◽  
Kane Model ◽  
Experimental Variation ◽  
Infra Red ◽  
Best Fit

Measurements of Faraday rotation and of infra-red plasma reflectance have been made at room temperature on n-type polycrystalline samples of GaASxSb1−x alloys. Hence effective mass values m00* for the bottom of the (000) conduction band have been determined. The experimental variation of m00* with x is compared with the predictions of various models, viz., (a) a simple Kane model, (b) the model proposed by Berolo et al., and (c) the model proposed by Hermann and Weisbuch. It is found that the model of Berolo et al. gives the best fit to the experimental data.

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