Raman Spectra of Cinnabar (HgS), Realgar (As4S4) and Orpiment (As2S3)

1969 ◽  
Vol 24 (3) ◽  
pp. 408-411 ◽  
Author(s):  
W. Scheuermann ◽  
G. J. Ritter
Keyword(s):  
Raman Spectra ◽  
Room Temperature ◽  
Laser Excitation ◽  
Structural Units ◽  
Raman Spectrometer ◽  
Partial Assignment ◽  
Naturally Occurring ◽  
Covalently Bonded ◽  
Infra Red

Abstract The Raman shifts in naturally occurring cinnabar (HgS), realgar (As4S4) and orpiment (As2S3) have been measured at room temperature using a photoelectrically recording Raman spectrometer with He-Ne laser excitation at 6328 Å. By using the infra-red spectra of these compounds it was possible to make a partial assignment of these shifts. The number and symmetries of the Raman active phonons were calculated for the covalently bonded "sub-units". Most of the theoretically predicted vibrations were observed. The theory that realgar and orpiment are built from the same structural units could be supported.

Electron Microscopy of Human Gallstones

1971 ◽  
Vol 29 ◽  
pp. 296-297
Author(s):  
C. Wolpers ◽  
R. Blaschke
Keyword(s):  
Electron Microscopy ◽  
Room Temperature ◽  
Bile Pigment ◽  
X Ray Diffraction ◽  
Triclinic Crystal System ◽  
X Ray ◽  
Follow Up Study ◽  
Infra Red ◽  
Main Components

Scanning microscopy was used to study the surface of human gallstones and the surface of fractures. The specimens were obtained by operation, washed with water, dried at room temperature and shadowcasted with carbon and aluminum. Most of the specimens belong to patients from a series of X-ray follow-up study, examined during the last twenty years. So it was possible to evaluate approximately the age of these gallstones and to get information on the intensity of growing and solving.Cholesterol, a group of bile pigment substances and different salts of calcium, are the main components of human gallstones. By X-ray diffraction technique, infra-red spectroscopy and by chemical analysis it was demonstrated that all three components can be found in any gallstone. In the presence of water cholesterol crystallizes in pane-like plates of the triclinic crystal system.

Naturally Occurring Organic Acid-catalyzed Facile Diastereoselective Synthesis of Biologically Active (E)-3-(arylimino)indolin-2-one Derivatives in Water at Room Temperature

2019 ◽  
Vol 23 (16) ◽  
pp. 1778-1788 ◽  
Author(s):  
Gurpreet Kaur ◽  
Arvind Singh ◽  
Kiran Bala ◽  
Mamta Devi ◽  
Anjana Kumari ◽  
...  
Keyword(s):  
Room Temperature ◽  
Biologically Active ◽  
Environmentally Benign ◽  
Diastereoselective Synthesis ◽  
Substituted Anilines ◽  
Reaction Conditions ◽  
Naturally Occurring ◽  
Acid Catalyzed ◽  
Reaction Media ◽  
Column Chromatographic

A simple, straightforward and efficient method has been developed for the synthesis of (E)-3-(arylimino)indolin-2-one derivatives and (E)-2-((4-methoxyphenyl)imino)- acenaphthylen-1(2H)-one. The synthesis of these biologically-significant scaffolds was achieved from the reactions of various substituted anilines and isatins or acenaphthaquinone, respectively, using commercially available, environmentally benign and naturally occurring organic acids such as mandelic acid or itaconic acid as catalyst in aqueous medium at room temperature. Mild reaction conditions, energy efficiency, good to excellent yields, environmentally benign conditions, easy isolation of products, no need of column chromatographic separation and the reusability of reaction media are some of the significant features of the present protocol.

scholarly journals Nonlinear Optical Response of a WS2 Monolayer at Room Temperature upon Multicolor Laser Excitation

ACS Photonics ◽  
2021 ◽  
Vol 8 (2) ◽  
pp. 550-556
Author(s):  
Javier Hernandez-Rueda ◽  
Marc L. Noordam ◽  
Irina Komen ◽  
L. Kuipers
Keyword(s):  
Nonlinear Optical ◽  
Room Temperature ◽  
Laser Excitation ◽  
Optical Response ◽  
Nonlinear Optical Response ◽  
Ws2 Monolayer

IR AND RAMAN SPECTROSCOPIC INVESTIGATIONS OF Cr2O3-TeO2-B2O3-SrO GLASSES

2004 ◽  
Vol 18 (09) ◽  
pp. 367-373 ◽  
Author(s):  
I. ARDELEAN ◽  
N. MUREŞAN ◽  
P. PĂŞCUŢĂ
Keyword(s):  
Raman Spectra ◽  
Glass Network ◽  
Ir And Raman Spectra ◽  
Structural Units ◽  
Raman Spectroscopic ◽  
Chromium Ions ◽  
Spectroscopic Investigations ◽  
Ir And Raman

The Cr 2 O 3 content influence on the structure of 70 TeO 2·25 B 2 O 3·5 SrO glasses, was investigated by infrared and Raman spectroscopies. The results show that BO 3 and BO 4 are among the main structural units in the investigated glasses, together with TeO 3 and TeO 4 units. The presence of chromium ions located in the glass network is well evidenced in the IR and Raman spectra.

A Miniaturized, No-Moving-Parts Raman Spectrometer

1993 ◽  
Vol 47 (5) ◽  
pp. 539-543 ◽  
Author(s):  
E. Neil Lewis ◽  
Patrick J. Treado ◽  
Ira W. Levin
Keyword(s):  
Solid State ◽  
Laser Excitation ◽  
Photon Counting ◽  
Avalanche Photodiode ◽  
Tunable Filter ◽  
Instrument Design ◽  
Laboratory Notebook ◽  
Raman Spectrometer ◽  
Digitally Controlled ◽  
Moving Parts

A solid-state acousto-optic tunable filter (AOTF) is combined with krypton laser excitation (647 nm), holographic Raman filters, and photon-counting silicon avalanche photodiode (APD) detection to construct a miniaturized Raman spectrometer with no moving parts. The physically compact AOTF and the highly integrated APD provide a rugged, digitally controlled spectrometer of moderate spectral resolution and with a footprint comparable in size to a laboratory notebook. Instrument design details are considered and representative spectra are reported. Potential areas of application for this prototype Raman spectrometer are also discussed.

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.

Photoluminescence of Ca4Ga2S7:Eu2+ in wide excitation intensity and temperature range

2021 ◽  
pp. 2150392
Author(s):  
B. D. Urmanov ◽  
M. S. Leanenia ◽  
G. P. Yablonskii ◽  
O. B. Taghiyev ◽  
K. O. Taghiyev ◽  
...  
Keyword(s):  
Room Temperature ◽  
Laser Excitation ◽  
Excitation Intensity ◽  
Temperature Measurements ◽  
Constant Time ◽  
Photoluminescence Properties ◽  
Temperature Range ◽  
Chalcogenide Semiconductors ◽  
Time Frames

Photoluminescence properties of [Formula: see text] chalcogenide semiconductors have been studied under the impulse laser excitation in the range of 10–105 W/cm2 at room temperature. This study has shown that as a result of excitation, photoluminescence of [Formula: see text] is characterized by the emission in the interval of 450–575 nm with significant domination in the spectra line at 660 nm. Photoluminescence of [Formula: see text] quenches at wavelengths of 560 nm and 660 nm with constant time frames 258 ns and 326 ns, respectively. Moreover, the temperature measurements of photoluminescence were performed on the samples in the temperature range of 10–300 K.

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