Infrared and Raman microscopy of fowl feather barb

1991 ◽  
Vol 69 (11) ◽  
pp. 1752-1757 ◽  
Author(s):  
Masamichi Tsuboi ◽  
Fumiko Kaneuchi ◽  
Teruki Ikeda ◽  
Kiso Akahane
Keyword(s):  
Raman Scattering ◽  
Laser Beam ◽  
Coordinate System ◽  
Key Words ◽  
Raman Spectra ◽  
Spectroscopic Measurement ◽  
Sheet Structure ◽  
Infrared Microscope ◽  
Polypeptide Chains ◽  
Pleated Sheet

A fowl feather barb 10 μm in thickness was subjected to a polarized infrared spectroscopic measurement by the use of a microscopic device. Nearly 50% of its peptide groups were found to give the 1633 and 1684 cm−1 bands characteristic of the antiparallel-chain pleated sheet structure, and the remaining 50% gave the 1659 cm−1 band assignable to unordered polypeptide chains. The orientation of the pleated sheet was determined to be on average θ = 52° and χ = 39°, where θ and χ are the angles for the transformation of the XYZ coordinate system fixed on the pleated sheet and the abc coordinate system fixed on the sample barb. The Raman spectra of the barb were also examined with another microscopic device and a 488.0-nm laser beam. A sharp aa component of the Raman scattering tensor was observed at 1667 cm−1. Based on this fact, a revised set of parameters for the vibrational couplings among the peptide groups in the pleated sheet has been proposed. Some discussions have been made on the amide I Raman tensor of the antiparallel-chain pleated sheet. Key words: fowl feather barb, Raman microscope, infrared microscope, antiparallel-chain pleated sheet, Raman scattering tensor.

scholarly journals Resonance and antiresonance in Raman scattering in GaSe and InSe crystals

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
M. Osiekowicz ◽  
D. Staszczuk ◽  
K. Olkowska-Pucko ◽  
Ł. Kipczak ◽  
M. Grzeszczyk ◽  
...  
Keyword(s):  
Raman Scattering ◽  
Temperature Effect ◽  
Band Gap ◽  
Raman Spectra ◽  
Quantum Interference ◽  
Optical Band Gap ◽  
Phonon Coupling ◽  
Phonon Modes ◽  
Electron Phonon Coupling ◽  
Resonant Raman

AbstractThe temperature effect on the Raman scattering efficiency is investigated in $$\varepsilon$$ ε -GaSe and $$\gamma$$ γ -InSe crystals. We found that varying the temperature over a broad range from 5 to 350 K permits to achieve both the resonant conditions and the antiresonance behaviour in Raman scattering of the studied materials. The resonant conditions of Raman scattering are observed at about 270 K under the 1.96 eV excitation for GaSe due to the energy proximity of the optical band gap. In the case of InSe, the resonant Raman spectra are apparent at about 50 and 270 K under correspondingly the 2.41 eV and 2.54 eV excitations as a result of the energy proximity of the so-called B transition. Interestingly, the observed resonances for both materials are followed by an antiresonance behaviour noticeable at higher temperatures than the detected resonances. The significant variations of phonon-modes intensities can be explained in terms of electron-phonon coupling and quantum interference of contributions from different points of the Brillouin zone.

scholarly journals X-RAY DIFFRACTION STUDIES ON AMYLOID FILAMENTS

1968 ◽  
Vol 16 (11) ◽  
pp. 673-677 ◽  
Author(s):  
E. D. EANES ◽  
G. G. GLENNER
Keyword(s):  
Polypeptide Chain ◽  
X Ray Diffraction ◽  
X Ray ◽  
Filament Axis ◽  
Adjacent Chain ◽  
Diffuse Halo ◽  
Sheet Structure ◽  
Regular Manner ◽  
Ray Patterns ◽  
Pleated Sheet

The filamentous protein component of amyloid-laden tissue was studied by x-ray diffraction procedures. The principal features of the x-ray pattern from nonoriented amyloid material consist of a sharp, intense ring at 4.75 Å overlaying a diffuse halo at 4.3 Å, and a broad and less intense ring at 9.8 Å. When oriented, the material gives a "cross-β" x-ray pattern. The x-ray findings are interpreted in terms of a "pleated sheet" structure formed by the amyloid polypeptide chain folding in a regular manner on itself such that adjacent chain segments are laterally arranged in an antiparallel manner. The x-ray patterns from oriented amyloid suggest further that the axes of the chain segments run transverse to the filament axis.

Stimulated Raman scattering of gaussian laser beam in relativistic plasma

Optik ◽  
2013 ◽  
Vol 124 (18) ◽  
pp. 3470-3475 ◽  
Author(s):  
Arvinder Singh ◽  
Keshav Walia
Keyword(s):  
Raman Scattering ◽  
Laser Beam ◽  
Stimulated Raman Scattering ◽  
Relativistic Plasma ◽  
Gaussian Laser Beam ◽  
Stimulated Raman

Stimulated Raman scattering of relativistic laser beam in plasmas

2005 ◽  
Vol 12 (4) ◽  
pp. 042302 ◽  
Author(s):  
H. A. Salih ◽  
S. T. Mahmoud ◽  
R. P. Sharma ◽  
M. Rafat
Keyword(s):  
Raman Scattering ◽  
Laser Beam ◽  
Stimulated Raman Scattering ◽  
Stimulated Raman

Raman Apparatus Using Laser Excitation and Polarization Measurements. Rotational Spectrum of Fluorine

1969 ◽  
Vol 23 (1) ◽  
pp. 8-12 ◽  
Author(s):  
Howard H. Claassen ◽  
Henry Selig ◽  
Jacob Shamir
Keyword(s):  
Laser Beam ◽  
Raman Spectra ◽  
Laser Excitation ◽  
Scattered Light ◽  
Rotational Constant ◽  
Emission Lines ◽  
Optical Systems ◽  
Rotational Spectrum ◽  
Polarization Measurements

Various schemes are compared for measuring depolarization factors in Raman spectra with laser excitation. Optical systems are discussed for producing a laser beam free of unwanted emission lines and for focusing scattered light on the slit and on the detector. The rotational spectrum of gaseous F2 has been used to determine a rotational constant of Bo=0.8841 ±0.0006 cm−1, corresponding to r0=1.4168±0.0005 Å.

Enhanced Raman Scattering of Elliptical Laser beam in a Collisional Plasma

2011 ◽  
Vol 51 (9) ◽  
pp. 788-797 ◽  
Author(s):  
A. Singh ◽  
K. Walia
Keyword(s):  
Raman Scattering ◽  
Laser Beam ◽  
Collisional Plasma ◽  
Enhanced Raman Scattering

Surface-Enhanced Raman Scattering of the Bariandite Oxide Layer on a Vanadium Dioxide Crystal

2011 ◽  
Vol 64 (12) ◽  
pp. 1621
Author(s):  
Ian S. Butler ◽  
James K. Beattie
Keyword(s):  
Raman Scattering ◽  
Raman Spectra ◽  
Vanadium Dioxide ◽  
Variable Temperature ◽  
Fold Increase ◽  
Surface Enhanced Raman Scattering ◽  
Surface Enhanced ◽  
Surface Enhanced Raman ◽  
Metal Phase Transition ◽  
Enhanced Raman Scattering

Variable-temperature (25–100°C) Raman spectra of a crystal of commercial VO2 have revealed surface-enhanced Raman scattering (SERS) of the V=O stretching mode of the bariandite-like vanadium oxide species, V10O24·9H2O, that is formed on the surface of the crystal. Upon passing through the semiconductor-to-metal phase transition of VO2 at 68°C, there is an approximately three to five-fold increase in Raman intensity of the V=O stretching mode. This effect is reversible with hysteresis upon decreasing the temperature. The temperature dependence of the Raman spectra at temperatures below the transition suggest that even the semiconductor phase has some SERS effect.

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