scholarly journals Mass-correlated rotational Raman spectra with high resolution, broad bandwidth, and absolute frequency accuracy

2018 ◽  
Vol 115 (20) ◽  
pp. 5072-5076 ◽  
Author(s):  
Christian Schröter ◽  
Jong Chan Lee ◽  
Thomas Schultz
Keyword(s):  
Raman Spectra ◽  
Optical Excitation ◽  
Rotational Transition ◽  
Observation Time ◽  
Absolute Frequency ◽  
Naturally Occurring ◽  
Order Of Magnitude ◽  
Quantum Wave ◽  
External Clock ◽  
Time And Energy

We present mass-correlated rotational alignment spectroscopy, based on the optical excitation of a coherent rotational quantum wave and the observation of temporal wave interferences in a mass spectrometer. Combined electronic and opto-mechanical delays increased the observation time and energy resolution by an order of magnitude compared with preceding time-domain measurements. Rotational transition frequencies were referenced to an external clock for accurate absolute frequency measurements. Rotational Raman spectra for six naturally occurring carbon disulfide isotopologues were resolved with 3 MHz resolution over a spectral range of 500 GHz. Rotational constants were determined with single-kilohertz accuracy, competitive with state-of-the-art frequency domain measurements.

scholarly journals Schwingungsspektroskopische Untersuchungen an Hydroxokomplexen des Zinks und Cadmiums / Vibrational Spectroscopic Investigations of Hydroxy Complexes of Zinc and Cadmium

1970 ◽  
Vol 25 (12) ◽  
pp. 1338-1344
Author(s):  
H. P. Fritz ◽  
W. Treptow
Keyword(s):  
Raman Spectra ◽  
Infrared And Raman Spectra ◽  
Spectroscopic Investigations ◽  
Order Of Magnitude

The infrared and Raman spectra of aqueous alkaline Zn(II) solutions and of crystalline tri-, tetra- and hexahydroxo zincate(II) and tetra- and hexahydroxocadmate(II) salts, respectively, are reported and discussed. Between 5 ᴍ and 15 ᴍ NaOH concentrations only the tetrahedral [Zn(ΟΗ)4]2⊖-ion is present in solution. Direct coordination of H2O to Zn(II) does not take place in an essential order of magnitude at any concentration

scholarly journals Transient birefringence of liquids induced by terahertz electric-field torque on permanent molecular dipoles

2017 ◽  
Vol 8 (1) ◽  
Author(s):  
Mohsen Sajadi ◽  
Martin Wolf ◽  
Tobias Kampfrath
Keyword(s):  
Dipole Moments ◽  
Excitation Frequency ◽  
Low Frequency ◽  
Optical Excitation ◽  
Thz Spectroscopy ◽  
Optical Pulses ◽  
Reorientational Motion ◽  
Translational Mode ◽  
Order Of Magnitude ◽  
Transient Birefringence

Abstract Collective low-frequency molecular motions have large impact on chemical reactions and structural relaxation in liquids. So far, these modes have mostly been accessed indirectly by off-resonant optical pulses. Here, we provide evidence that intense terahertz (THz) pulses can resonantly excite reorientational-librational modes of aprotic and strongly polar liquids through coupling to the permanent molecular dipole moments. We observe a significantly enhanced response because the transient optical birefringence is up to an order of magnitude higher than obtained with optical excitation. Frequency-dependent measurements and a simple analytical model indicate that the enhancement arises from resonantly driven librations and their coupling to reorientational motion, assisted by the pump field and/or a cage translational mode. Our results open up the path to applications such as efficient molecular alignment, enhanced transient Kerr signals and systematic resonant nonlinear THz spectroscopy of the coupling between intermolecular modes in liquids.

Optical Excitation of the Rotational Transition of Methane in Condensed Xenon

1978 ◽  
Vol 44 (5) ◽  
pp. 1755-1756 ◽  
Author(s):  
Takao Nanba ◽  
Minoru Sagara ◽  
Mikihiko Ikezawa
Keyword(s):  
Optical Excitation ◽  
Rotational Transition

scholarly journals Far Wing Asymmetry of Rotational Raman Lines in Hydrogen

2010 ◽  
Vol 2010 ◽  
pp. 1-5 ◽  
Author(s):  
Magnus Gustafsson
Keyword(s):  
Raman Spectra ◽  
Line Profile ◽  
Threshold Energy ◽  
Rotational Transition ◽  
Hydrogen Gas ◽  
Shape Resonance ◽  
Pure Hydrogen ◽  
Line Shapes ◽  
Significant Intensity

Depolarized Raman spectra of compressed hydrogen gas have been computed rigorously previously for 36 K and 50 K (Gustafsson et al. (2009)). The far wings of the rotational lines show asymmetry that goes beyond that expected from the theory for intracollisional interference and Fano line shapes. Here we analyze the (0) line for pure hydrogen at 36 K in detail. The added asymmetry stems partly from a shape resonance which adds significant intensity to the higher frequency side of the line profile. The influence of the threshold energy for the rotational transition accounts for the remainder.

scholarly journals Meridianiite detected in ice

2009 ◽  
Vol 55 (189) ◽  
pp. 117-122 ◽  
Author(s):  
F. Elif Genceli ◽  
Shinichirou Horikawa ◽  
Yoshinori Iizuka ◽  
Toshimitsu Sakurai ◽  
Takeo Hondoh ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Low Temperature ◽  
Sea Ice ◽  
Magnesium Sulfate ◽  
Raman Spectra ◽  
Sulfate Salt ◽  
Micro Raman Spectroscopy ◽  
Naturally Occurring ◽  
Formation History ◽  
History Of

AbstractInclusions affect the behavior of ice, and their characteristics help us understand the formation history of the ice. Recently, a low-temperature magnesium sulfate salt was discovered. This paper describes this naturally occurring MgSO4·11H2O mineral, meridianiite, derived from salt inclusions in sea ice of Lake Saroma, Japan and in Antarctic continental core ice. Its occurrence is confirmed by using micro-Raman spectroscopy to compare Raman spectra of synthetic MgSO4·11H2O with those of the inclusions.

A comparative study of AlGaN- and GaN-based lasing structures for near- and deep-UV applications

2000 ◽  
Vol 622 ◽  
Author(s):  
Sergiy Bidnyk ◽  
Jack B. Lam ◽  
Gordon G. Gainer ◽  
Brian D. Little ◽  
Yong-Hwan Kwon ◽  
...  
Keyword(s):  
Uv Light ◽  
Optical Excitation ◽  
Stimulated Emission ◽  
Lasing Threshold ◽  
Time Resolved ◽  
Light Emitting Devices ◽  
Temperature Range ◽  
Critical Issues ◽  
Order Of Magnitude ◽  
Deep Uv

ABSTRACTWe report a comprehensive study on the optical properties of GaN- and AlGaN-based lasing structures at high-levels of optical excitation (carrier densities of 1017−1020 cm−3) and identify critical issues necessary for the development of near- and deep-UV light emitting devices. We successfully achieved room temperature stimulated emission (SE) with emission wavelengths ranging from 351 nm to 373 nm in a variety of samples. Through an analysis of the temperature-dependent lasing characteristics, combined with absorption and time-resolved photoluminescence measurements, we estimated the carrier density required to achieve the SE threshold in GaN epilayers. We found that in AlGaN epilayers, the onset of SE (∼1019 cm−3) occurs at carrier densities one order of magnitude higher than in thick GaN epilayers, indicating that an electron-hole plasma is the dominant gain mechanism over the entire temperature range studied (10 K to 300 K). A remarkably low lasing threshold was observed in GaN/AlGaN heterostructures over the temperature range of 10 K to 300 K. Our experimental results indicate that GaN/AlGaN heterostructures could be used to efficiently generate laser emission with wavelengths shorter than 373 nm. The implications of this study on the development of UV laser diodes is discussed.

Response of Soot Temperature to Unsteady Inlet Airflow Under Modulated Condition and Naturally Occurring Combustion Dynamics

2015 ◽  
Vol 137 (4) ◽  
Author(s):  
Michael Knadler ◽  
Arda Cakmakci ◽  
Jong Guen Lee
Keyword(s):  
Temperature Fluctuation ◽  
Jet Fuel ◽  
Soot Temperature ◽  
Measured Temperature ◽  
Combustion Dynamics ◽  
Flow Modulation ◽  
Naturally Occurring ◽  
Flame Emission ◽  
Order Of Magnitude ◽  
Modulation Level

The response of soot temperature to unsteady inlet airflow is characterized using pyrometry. The unsteady inlet airflow is achieved by either modulating inlet air or naturally occurring unstable flame, running on a jet fuel at fuel-rich conditions. The inlet air is modulated by a siren device running at frequencies between 150 and 250 Hz and up to 60% of modulation level (u'/um) is achieved. Also, the combustor can be run naturally unstable at the same inlet operating condition by changing the combustor length. For pyrometry, the emission from whole flame at 660 nm, 730 nm, and 800 nm is recorded and the three-color pyrometry is used to measure soot temperature. The effect of nonisothermal distribution of soot in flame on the measured temperature is also considered. The level of overall temperature fluctuation under inlet flow modulation (Trms/Tmean) is about an order of magnitude lower than that of flame emission fluctuation (Irms/Imean). Under naturally occurring instability, the measured soot temperature is in phase with the pressure measured in the combustor, indicating that the measured soot temperature can be used as a quantity related to combustion dynamics for fuel-rich sooty flames.

scholarly journals A new microwave spectrometer for ground-based observations of water vapour

2013 ◽  
Vol 6 (3) ◽  
pp. 4677-4703 ◽  
Author(s):  
K. Hallgren ◽  
P. Hartogh ◽  
C. Jarchow
Keyword(s):  
Water Vapour ◽  
Time Resolution ◽  
Middle Atmosphere ◽  
Signal To Noise Ratio ◽  
Rotational Transition ◽  
High Time Resolution ◽  
Error Sources ◽  
Order Of Magnitude ◽  
Optical Table ◽  
Heterodyne Spectrometer

Abstract. We have developed a new, high time-resolution, microwave heterodyne spectrometer for observations of water vapour in the middle atmosphere. It measures the rotational transition of water vapour at 22.235 GHz in the vertical and horizontal polarisation. The two polarisations are averaged in order to optimise the signal-to-noise ratio. The different polarisations have separate, but identical, signal chains consisting of a 22 GHz cooled HEMT amplifier, a second, warm, 22 GHz HEMT booster amplifier, an IF stage and a Chirp Transform Spectrometer (CTS) backend. Continuous calibration with two internal loads kept at temperatures close to the observed atmosphere, a wobbling optical table to reduce standing waves in the optical path and the low receiver temperature ensures a time resolution of an order of magnitude better than what has been achieved by earlier instruments. The error sources in the retrieved spectrum are discussed and the data is compared and validated against EOS-MLS on the NASA Aura satellite. The profiles are found to be in good agreement with each other.

scholarly journals Double-Layer Plaque Assay for Quantification of Enteroviruses

2004 ◽  
Vol 70 (5) ◽  
pp. 2801-2805 ◽  
Author(s):  
Laura Mocé-Llivina ◽  
Francisco Lucena ◽  
Juan Jofre
Keyword(s):  
Double Layer ◽  
Carcinoma Cell ◽  
Plaque Assay ◽  
Most Probable Number ◽  
Suspended Cell ◽  
Probable Number ◽  
Membrane Filters ◽  
Naturally Occurring ◽  
Order Of Magnitude ◽  
Virus Quantification

ABSTRACT We describe here a double-layer plaque assay for the quantification of enteroviruses, combining a monolayer plaque assay and a suspended-cell plaque assay. The double-layer assay provides significantly greater counts than other methods of virus quantification of both suspensions of pure culture viruses and naturally occurring viruses. The counts obtained by this method are approximately one order of magnitude greater than those obtained with the more commonly used method, the monolayer plaque assay. We conclude that the methods available for quantifying viruses rank in efficiency as follows: double-layer plaque assay ≥ suspended-cell plaque assay > counting cytopathogenic virus adsorbed to cellulose nitrate membrane filters ≥ most probable number of cytopathogenic units > monolayer plaque assay. Moreover, the double-layer plaque assay allows the use of two different cell lines in the two layers. Using the human colonic carcinoma cell line CaCo2 facilitates the recovery of a greater number and diversity of naturally occurring enteroviruses in water than the monolayer agar method. In addition, the pretreatment of cells with 5-iodo-2′-deoxyuridine (IDU) prior to the quantification of enteroviruses by the double-layer plaque assay provides significantly higher recoveries than the use of IDU does with the other methods of quantification.

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