Broadening and shifting of the depolarized component of the Raman Q branch in D2 at room temperature

1995 ◽  
Vol 73 (7-8) ◽  
pp. 530-536 ◽  
Author(s):  
P. M. Sinclair ◽  
P. Duggan ◽  
J. R. Drummond ◽  
A. D. May
Keyword(s):  
Spectral Data ◽  
Direct Measurement ◽  
Room Temperature ◽  
Theoretical Calculations

We report the first direct measurement of the broadening and shifting of the depolarized component of the Raman Q branch in D2. Spectral data were recorded from 1.5 to 12 amagat at 305.2 K. Both the measured broadening and shifting of the depolarized component are significantly different from that for the polarized Q branch. These results can be used as a check of theoretical calculations when they become available. Here they are used to correct previously reported values of the broadening of the polarized part of the Q-branch spectrum. Measured values of the ratio of the depolarized to polarized intensity for the Q-branch lines are also given.

scholarly journals Nonreciprocal charge transport up to room temperature in bulk Rashba semiconductor α-GeTe

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Yan Li ◽  
Yang Li ◽  
Peng Li ◽  
Bin Fang ◽  
Xu Yang ◽  
...  
Keyword(s):  
Charge Transport ◽  
Room Temperature ◽  
Theoretical Calculations ◽  
Ferromagnetic Layer ◽  
Spin Splitting ◽  
New Paradigm ◽  
Rashba Spin ◽  
Rashba Spin Splitting ◽  
Fundamental Insight ◽  
Insight Into

AbstractNonmagnetic Rashba systems with broken inversion symmetry are expected to exhibit nonreciprocal charge transport, a new paradigm of unidirectional magnetoresistance in the absence of ferromagnetic layer. So far, most work on nonreciprocal transport has been solely limited to cryogenic temperatures, which is a major obstacle for exploiting the room-temperature two-terminal devices based on such a nonreciprocal response. Here, we report a nonreciprocal charge transport behavior up to room temperature in semiconductor α-GeTe with coexisting the surface and bulk Rashba states. The combination of the band structure measurements and theoretical calculations strongly suggest that the nonreciprocal response is ascribed to the giant bulk Rashba spin splitting rather than the surface Rashba states. Remarkably, we find that the magnitude of the nonreciprocal response shows an unexpected non-monotonical dependence on temperature. The extended theoretical model based on the second-order spin–orbit coupled magnetotransport enables us to establish the correlation between the nonlinear magnetoresistance and the spin textures in the Rashba system. Our findings offer significant fundamental insight into the physics underlying the nonreciprocity and may pave a route for future rectification devices.

scholarly journals SYNTHESIS, CHARACTERIZATION AND ANTIOXIDANT ACTIVITY OF 7-HYDROXY-3',4'-DIMETHOXYFLAVONE

2012 ◽  
Vol 12 (2) ◽  
pp. 146-151 ◽  
Author(s):  
Elfi Susanti VH ◽  
Sabirin Matsjeh ◽  
Tutik Dwi Wahyuningsih ◽  
Mustofa Mustofa ◽  
Tri Redjeki
Keyword(s):  
Aqueous Solution ◽  
Antioxidant Activity ◽  
Sodium Hydroxide ◽  
Spectral Data ◽  
1H Nmr ◽  
13C Nmr ◽  
Room Temperature ◽  
Antioxidant Activities ◽  
Oxidative Cyclization ◽  
Dpph Method

Synthesis of flavones and their derivatives has attracted considerable attention due to their significant pharmaceutical effects. 7-hydroxy-3',4'-dimethoxyflavone has been synthesized and its antioxidant activity has been investigated. Flavone was synthesized by oxidative cyclization of chalcone. 2',4'-dihydroxy-3,4-dimethoxychalcone was prepared by Claisen-Schmidt condensation of 2,4-dihydroxyacetophenones with 3,4-dimethoxybenzaldehydes in the presence of aqueous solution of sodium hydroxide and ethanol at room temperature. Oxidative cyclization of 2',4'-dihydroxy-3,4-dimethoxychalcone was done by using I2 catalyst in DMSO to form 7-hydroxy-3',4'-dimethoxyflavone. The synthesized compounds were characterized by means of their UV-Vis, IR, 1H-NMR and 13C-NMR spectral data. The compound was tested for their antioxidant activities by DPPH method.

scholarly journals Finite-temperature violation of the anomalous transverse Wiedemann-Franz law

2020 ◽  
Vol 6 (17) ◽  
pp. eaaz3522 ◽  
Author(s):  
Liangcai Xu ◽  
Xiaokang Li ◽  
Xiufang Lu ◽  
Clément Collignon ◽  
Huixia Fu ◽  
...  
Keyword(s):  
Wave Function ◽  
Inelastic Scattering ◽  
Finite Temperature ◽  
Room Temperature ◽  
Theoretical Calculations ◽  
Data Accuracy ◽  
Berry Curvature ◽  
Curvature Distribution ◽  
Open Question ◽  
Transverse Response

The Wiedemann-Franz (WF) law has been tested in numerous solids, but the extent of its relevance to the anomalous transverse transport and the topological nature of the wave function, remains an open question. Here, we present a study of anomalous transverse response in the noncollinear antiferromagnet Mn3Ge extended from room temperature down to sub-kelvin temperature and find that the anomalous Lorenz ratio remains close to the Sommerfeld value up to 100 K but not above. The finite-temperature violation of the WF correlation is caused by a mismatch between the thermal and electrical summations of the Berry curvature and not by inelastic scattering. This interpretation is backed by our theoretical calculations, which reveals a competition between the temperature and the Berry curvature distribution. The data accuracy is supported by verifying the anomalous Bridgman relation. The anomalous Lorenz ratio is thus an extremely sensitive probe of the Berry spectrum of a solid.

Assessment of the performance of quantitative feature-based transfer learning LIBS analysis of chromium in high temperature alloy steel samples

2020 ◽  
Vol 35 (11) ◽  
pp. 2639-2648
Author(s):  
Fu Chang ◽  
Huili Lu ◽  
Hao Sun ◽  
Jianhong Yang
Keyword(s):  
Hilbert Space ◽  
High Temperature ◽  
Regression Model ◽  
Spectral Data ◽  
Transfer Learning ◽  
Alloy Steel ◽  
Room Temperature ◽  
High Temperature Alloy ◽  
Feature Based ◽  
Calibration Samples

The spectral data of calibration samples at room temperature and the spectral data of uncalibrated samples at high temperature are together transferred into a Hilbert space where an LIBS regression model is established.

Carbocyclization in natural products. III. Brominative cyclization of dehydrosaussurea lactone and costunolide

1980 ◽  
Vol 58 (5) ◽  
pp. 447-449 ◽  
Author(s):  
Tikam C. Jain ◽  
Calvin M. Banks
Keyword(s):  
Natural Products ◽  
Spectral Data ◽  
Room Temperature ◽  
Aqueous Acetone

Treatment of dehydrosaussurea lactone 4 and costunolide 1 with N-bromosuccinimide (NBS) in aqueous acetone at room temperature furnished bromolactones 6, 7, and 8. Structural evidence for these bromolactones rests upon spectral data and transformation to the hydrogenated bromolactones 9, 10, and 11. The latter were found identical with the corresponding products obtained by the brominative cyclization of dihydrocostunolide 2.

Spectroscopic Investigation of V3+:YAG Crystal

2013 ◽  
Vol 774-776 ◽  
pp. 811-815 ◽  
Author(s):  
Jian Ma
Keyword(s):  
Room Temperature ◽  
Factor Model ◽  
Theoretical Calculations ◽  
Czochralski Method ◽  
Experiment Data ◽  
Crystal Field Theory ◽  
Calculation Results ◽  
First Time ◽  
Pure Argon Atmosphere ◽  
Good Agreement

V3+ions doped YAG crystals were grown using the Czochralski method in a highly pure argon atmosphere. The transmission spectrum of trivalent vanadium in YAG crystal has been measured at room temperature. Eight bands were observed in which two bands centered at 690nm (14493cm-1) and 1490nm (6711cm-1) are reported for the first time. By using the crystal-field theory and introducing the average covalent factor model, we also presented the theoretical calculations of the energy level splitting of tetrahedrally coordinated V3+impurity systems in YAG crystal. These calculation results are in good agreement with the optical experiment data.

Novel Diastereoselective Synthesis of 1-Trimethylgermyl-1-alkenes by Hydrolysis of α-Trimethylgermylzirconacyclopentenes

2020 ◽  
Vol 5 (2) ◽  
pp. 161-163
Author(s):  
Narayan G. Bhat ◽  
Maria Villarreal
Keyword(s):  
Low Temperature ◽  
Spectral Data ◽  
Room Temperature ◽  
Nitrogen Atmosphere ◽  
Terminal Alkynes ◽  
Diastereoselective Synthesis ◽  
Butyl Lithium ◽  
Hydrolysis Of

1-Trimethyl-1-germylalkynes were synthesized by deprotonation of terminal alkynes with n-butyl lithium at low temperature followed by treatment with trimethylgermyl chloride under nitrogen atmosphere. The reagent system Cp2ZrCl2/2EtMgBr converts 1-trimethylgermyl-1-alkynes into α- trimethylgermylzirconacyclopentenes at -78 ºC for 1 h followed by stirring at room temperature overnight. These novel intermediates are hydrolyzed at 0 ºC for an hour to provide the corresponding (Z)-1-trimethylgermyl-1-alkenes in good yields (74-85%) and in high stereochemical purities (> 98%) as evidenced by 13C spectral data.

Experimental Determination of Line Strengths for Selected Carbon Monoxide and Carbon Dioxide Absorption Lines at Temperatures between 295 and 1250 K

1994 ◽  
Vol 48 (11) ◽  
pp. 1442-1450 ◽  
Author(s):  
Patrick J. Medvecz ◽  
Kenneth M. Nichols
Keyword(s):  
Fourier Transform ◽  
High Temperature ◽  
Absorption Spectra ◽  
High Temperatures ◽  
Room Temperature ◽  
Theoretical Calculations ◽  
Line Strength ◽  
Temperature Data ◽  
Line Strengths

Fourier transform infrared absorption spectroscopy has been used for the determination of the line strengths of 41 CO and CO2 absorption lines at temperatures between 295 and 1250 K. The CO vibrational-rotational lines were from the P branch of the fundamental absorption band (2150–1950 cm−1) while the CO2 vibrational-rotational lines were from the far wing of the R branch of the v3 fundamental band (2395–2380 cm−1). The intensities of the lines were measured from absorption spectra recorded in a high-temperature gas cell containing known concentrations of CO/CO2/N2 gas mixtures at atmospheric pressure. Absorption spectra were recorded through the cell with the use of a moderate-resolution Fourier transform infrared spectrometer. The absorption spectra were mathematically corrected for distortions resulting from the finite resolution of the spectrometer and for peak overlap. Line strength measurements were made from the corrected peaks by using the Bouguer-Lambert law and assuming a Lorenztian line profile. The experimentally obtained line strengths were evaluated (1) by statistical calculations, (2) by consideration of the validity of the Bouguer-Lambert assumption for these data, (3) by comparison with existing room-temperature and high-temperature data, and (4) by comparison with theoretical calculations. For CO, the statistical analysis suggests that the reported values have an uncertainty of ±10–12%, which is similar to the observed discrepancies with other reported values at room temperature. At high temperatures, the difference between these data and previously reported data and theoretical predictions is less than 10%. For CO2, the statistical uncertainty associated with the line strength calculations is less than 5%, which is also the approximate level of agreement with existing room-temperature data. For lines with m indicies of 65–89, at high temperatures, the values reported in this work agree within 5 to 10% of theoretical calculations.

Acyl-und Alkylidenphosphane, XV 2.2-Dimethylpropylidinphosphan, eine stabile Verbindung mit einem Phosphoratom der Koordinationszahl 1/ Acyl- and Alkylidenephosphines, XV 2,2-Dimethylpropvlidynephosphine, a Stable Compound with a Phosphorus Atom of Coordination Number 1

1981 ◽  
Vol 36 (1) ◽  
pp. 16-19 ◽  
Author(s):  
Gerd Becker ◽  
Gudrun Gresser ◽  
Werner Uhl
Keyword(s):  
Mass Spectrum ◽  
Sodium Hydroxide ◽  
Coordination Number ◽  
Spectral Data ◽  
Phosphorus Atom ◽  
Room Temperature ◽  
Stable Compound

Abstract In the presence of small amounts of solid sodium hydroxide, [2,2-dimethyl-l-(trimethylsiloxy)propylidene]-trimethylsilylphosphine reacts at + 20 °C to give hexamethyldisiloxane and 2,2-dimethylpropylidynephosphine (2). In contrast to similar alkylidynephosphines this compound is stable at room temperature. The IR and mass spectrum are discussed, and 1H, 13C and 31P NMR spectral data are given.

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