Rotational freedom of HCl and the methyl halides in solution as shown by the contours of infra-red absorption bands

1960 ◽  
Vol 56 ◽  
pp. 625 ◽  
Author(s):  
W. J. Jones ◽  
N. Sheppard
Keyword(s):  
Absorption Bands ◽  
Methyl Halides ◽  
Infra Red ◽  
Rotational Freedom

The intensities of absorption bands in the methyl halides

1952 ◽  
Vol 213 (1112) ◽  
pp. 27-41 ◽  
Keyword(s):  
Dipole Moment ◽  
Methyl Iodide ◽  
Fermi Resonance ◽  
Pressure Broadening ◽  
Fundamental Vibration ◽  
Absorption Bands ◽  
Methyl Halides ◽  
Methyl Fluoride ◽  
Molecular Dipole ◽  
Infra Red

The infra-red intensities of the fundamental vibration bands of the four methyl halides have been measured, using the method involving pressure broadening of bands described by Wilson. The force constants have been determined on the basis of a force field previously suggested by Noether, and the transformations from normal to symmetry co-ordinates have been calculated. After allowing for the effects of the overlapping of bands and of Fermi resonance, the intensities have been interpreted in terms of bond moments μ and of their derivatives ∂ μ /∂ r , assumed to be vectors directed along the bonds. The results show that values of ∂ μ /∂ r CH obtained from the A 1 class of vibration vary from about 1⋅7 x 10 -10 unit (Debye/Å) for methyl fluoride to about 0⋅9 x 10 -10 for methyl iodide showing a uniform trend along the series. By contrast, the values in the E class range from about 0⋅6 x 10 -10 for methyl fluoride to less than 0⋅2 x 10 -10 for the iodide. Values of μ CH in general lie around 0⋅4 D. ∂ μ /∂ r CX increases in value from 1 x 10 -10 unit in methyl iodide to the high value of 4⋅7 x 10 -10 unit in methyl fluoride. There is some indication that its sign is positive. Values of μ CF and of μ CCl are obtained which are considerably higher than the total molecular dipole moment. Some tentative suggestions are put forward to account for the magnitudes of the polar properties found.

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.

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.

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).

scholarly journals Emission and absorption in the infra-red spectra of mercury, zinc, and cadmium

1919 ◽  
Vol 95 (669) ◽  
pp. 280-299 ◽  
Keyword(s):  
White Light ◽  
Vapour Pressure ◽  
Wave Length ◽  
Mercury Vapour ◽  
Stimulate Emission ◽  
First Line ◽  
Absorption Bands ◽  
Infra Red ◽  
Partial Parallelism ◽  
Lower Voltage

In a previous paper the writer pointed out that well-marked absorption bands exist in the infra-red region of the spectrum caused by passing white light through non-luminous mercury vapour. These bands occur at λ 1·014, λ 1·129. and λ 1·205, the first and third of these being especially strong. This investigation has since been extended further into the infra-red with mercury vapour, and it has also been repeated with the vapours of zinc and cadmium in place of that of mercury. The results serve to establish at least a partial parallelism in the behaviour of the three metals, the resemblance being most marked in the region of the first line of the series represented by v = (2·5, S)—( m , P), at which wave-length absorption takes place in the case of all three metals with extremely small vapour-pressure. On account of the ease with which the wave-length corresponding to v = (2·5, S)—( m , P) was absorbed, it was suspected that it should be emitted under electronic bombardment. At the suggestion of Prof. McLennan an investigation was undertaken with mercury vapour, in order to determine the speed which electrons must be given in order to stimulate emission of the wave-length λ 1·014. If we apply the quantum relation ve = hv to the frequency of this wave-length, we get V = 1·26 volts. In the experiments which will be described herein, the wave-length λ 1·014 was actually emitted with a voltage as low as 5 volts. There were strong indications that even a lower voltage would suffice to stimulate emission of the wave-length, but under the conditions of the experiment the radiations of this wave-length when emitted were reabsorbed by the intervening layers of mercury vapour.

Infra-Red Spectroscopy Analysis of Malva Fibers

2014 ◽  
Vol 775-776 ◽  
pp. 255-260 ◽  
Author(s):  
Sergio Neves Monteiro ◽  
Frederico Muylaert Margem ◽  
Jean Igor Margem ◽  
Lucas Barbosa de Souza Martins ◽  
Caroline Gonçalves Oliveira ◽  
...  
Keyword(s):  
Fourier Transform ◽  
Ftir Spectroscopy ◽  
Polymer Composites ◽  
Environmentally Friendly ◽  
Spectroscopy Analysis ◽  
Absorption Bands ◽  
Lignocellulosic Fibers ◽  
Lignocellulosic Fiber ◽  
Synthetic Materials ◽  
Infra Red

The growing interest for natural materials as an environmentally friendly alternative for the substitution of energy intensive and non-sustainable synthetic materials, has motivated the use of lignocellulosic fibers as reinforcement of polymer composites. The malva fiber, a relatively unknown lignocellulosic fiber with potential for composite reinforcement, still needs to be characterized for possible engineer applications. Therefore, the present work analyzed the malva fiber by means of Fourier Transform Infra-red (FTIR) spectroscopy. The malva fiber FTIR spectrum revealed main absorption bands typical of any lignocellulosic fiber. However, some specific bands as well as bands broadening and intensity suggested particular activities for functional molecular groups in the malva fiber.

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