scholarly journals Terahertz Gas-Phase Spectroscopy Using a Sub-Wavelength Thick Ultrahigh-Q Microresonator

Sensors ◽  
2020 ◽  
Vol 20 (10) ◽  
pp. 3005 ◽  
Author(s):  
Dominik Walter Vogt ◽  
Angus Harvey Jones ◽  
Rainer Leonhardt
Keyword(s):  
Gas Phase ◽  
Water Vapour ◽  
Gas Detection ◽  
Proof Of Concept ◽  
Atmospheric Conditions ◽  
Frequency Range ◽  
Trace Level ◽  
Terahertz Spectrum ◽  
Gas Phase Spectroscopy ◽  
Sub Wavelength

The terahertz spectrum provides tremendous opportunities for broadband gas-phase spectroscopy, as numerous molecules exhibit strong fundamental resonances in the THz frequency range. However, cutting-edge THz gas-phase spectrometer require cumbersome multi-pass gas cells to reach sufficient sensitivity for trace level gas detection. Here, we report on the first demonstration of a THz gas-phase spectrometer using a sub-wavelength thick ultrahigh-Q THz disc microresonator. Leveraging the microresonator’s ultrahigh quality factor in excess of 120,000 as well as the intrinsically large evanescent field, allows for the implementation of a very compact spectrometer without the need for complex multi-pass gas cells. Water vapour concentrations as low as 4 parts per million at atmospheric conditions have been readily detected in proof-of-concept experiments.

Supersonic molecular beam and static gas phase spectroscopy of intermolecular hot bands associated with ν116O12C---1H19F

1988 ◽  
Vol 152 (1) ◽  
pp. 87-93 ◽  
Author(s):  
K. McMillan ◽  
D. Bender ◽  
M. Eliades ◽  
D. Danzeiser ◽  
B.A. Wofford ◽  
...  
Keyword(s):  
Gas Phase ◽  
Molecular Beam ◽  
Supersonic Molecular Beam ◽  
Gas Phase Spectroscopy

scholarly journals Discrimination of patterns of N-acetylation in chitooligosaccharides by gas phase IR spectroscopy integrated to mass spectrometry

2017 ◽  
Vol 89 (9) ◽  
pp. 1349-1357 ◽  
Author(s):  
Jasper Wattjes ◽  
Baptiste Schindler ◽  
Stéphane Trombotto ◽  
Laurent David ◽  
Bruno M. Moerschbacher ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Ir Spectroscopy ◽  
Gas Phase ◽  
Dimensional Analysis ◽  
Unique Combination ◽  
Structural Detail ◽  
Chitosan Oligosaccharides ◽  
Infra Red ◽  
Rapid Discrimination ◽  
Gas Phase Spectroscopy

AbstractWe propose a novel, bi-dimensional analysis of partially N-acetylated chitosan oligosaccharides based on gas phase Infra-Red spectroscopy integrated to mass spectrometry (MS). By providing simultaneously MS and IR fingerprints, this approach combines the advantages of MS with the refined structural detail offered by gas phase spectroscopy and provides robust signatures for the rapid discrimination of the patterns of N-acetylation. Four mono-N-deacetylated and two doubly-N-deacetylated chitosan tetramer standards with well-defined patterns of acetylation were produced and analyzed by IR integrated to MS. We show that each sequence displays a unique combination of MS and IR fingerprints, thus offering a rapid diagnostic for the pattern of acetylation without the need for reducing end labeling.

scholarly journals Diastereo-specific conformational properties of neutral, protonated and radical cation forms of (1R,2S)-cis- and (1R,2R)-trans-amino-indanol by gas phase spectroscopy

2015 ◽  
Vol 17 (39) ◽  
pp. 25809-25821 ◽  
Author(s):  
Aude Bouchet ◽  
Johanna Klyne ◽  
Giovanni Piani ◽  
Otto Dopfer ◽  
Anne Zehnacker
Keyword(s):  
Electronic Structure ◽  
Gas Phase ◽  
Radical Cation ◽  
Amino Alcohol ◽  
Uv Spectroscopy ◽  
Conformational Properties ◽  
Gas Phase Spectroscopy ◽  
Ir And Uv Spectroscopy

The effects of ionisation and protonation on the geometric and electronic structure of a prototypical aromatic amino-alcohol with two chiral centres are revealed by IR and UV spectroscopy.

scholarly journals Optimal Estimation MSG-SEVIRI Clear-Sky Total Column Water Vapour Retrieval Using the Split Window Difference

Atmosphere ◽  
2021 ◽  
Vol 12 (10) ◽  
pp. 1256
Author(s):  
Jan El Kassar ◽  
Cintia Carbajal Henken ◽  
Rene Preusker ◽  
Jürgen Fischer
Keyword(s):  
Water Vapour ◽  
Large Scale ◽  
Pearson Correlation ◽  
Microwave Radiometer ◽  
Optimal Estimation ◽  
Forward Model ◽  
Observation Data ◽  
Atmospheric Conditions ◽  
Uncertainty Estimates ◽  
Total Column

A new algorithm for the retrieval of day-time total column water vapour (TCWV) from measurements of a MSG-SEVIRI (Meteosat Second Generation Spinning Enhanced Visible and Infrared Imager) instrument is presented. The retrieval is based on a forward operator, at the core of which lies Radiative Transfer for TIROS Operational Vertical Sounder (RTTOV). This forward model relates TCWV and surface temperature to brightness temperatures in the split window at 11 and 12µm with the use of a first guess for temperature and humidity profiles from the ERA5 reanalysis. The forward model is then embedded in a full Optimal Estimation (OE) method, which yields pixel by pixel uncertainty estimates and performance indicators. The algorithm is applicable to any instrument which features the split window configuration, given a first guess for atmospheric conditions (i.e., from NWP) and an estimate of surface emissivity at 11 µm. The algorithm was developed within the framework of RealPEP (Near-Realtime Quantitative Precipitation Estimation and Prediction) in which the advancement of the estimation and nowcasting of extreme precipitation and flooding in Germany are studied. Thus, processing and validation has been limited to the German domain. Three independent ground-based TCWV observation data sets were used as reference, i.e., AERONET (Aerosol Robotic Network), GNSS Germany (Global Navigation Satellite System) and measurements from two MWR (Microwave Radiometer) sites. The validation concludes with good agreement, with absolute biases between 0.11 and 2.85 kg/m2, root mean square deviations (rmsds) between 1.63 and 3.24 kg/m2 and Pearson correlation coefficients ranging from 0.96 to 0.98. The retrievals uncertainty estimates were evaluated against AERONET. The comparison suggests that, in sum, uncertainties are estimated well, while still some error sources seem to be over- and underestimated. In limited case studies it could be shown that SEVIRI TCWV is capable to both display large scale variabilities in water vapour fields and reproduce the daily course of water vapour exposed by ground-based observations.

scholarly journals Quantitative estimates of the volatility of ambient organic aerosol

2010 ◽  
Vol 10 (1) ◽  
pp. 1901-1938 ◽  
Author(s):  
C. D. Cappa ◽  
J. L. Jimenez
Keyword(s):  
Los Angeles ◽  
Gas Phase ◽  
Organic Aerosol ◽  
Basis Sets ◽  
Volatile Fraction ◽  
Volatile Components ◽  
Atmospheric Conditions ◽  
Volatile Material ◽  
Evaporation Coefficient ◽  
Quantitative Estimates

Abstract. Measurements of the sensitivity of organic aerosol (OA, and its components) mass to changes in temperature were recently reported by Huffman et al. (2009) using a tandem thermodenuder-aerosol mass spectrometer (TD-AMS) system in Mexico City and the Los Angeles area. Here, we use these measurements to derive quantitative estimates of aerosol volatility within the framework of absorptive partitioning theory using a kinetic model of aerosol evaporation in the TD. OA volatility distributions (or "basis-sets") are determined using several assumptions as to the enthalpy of vaporization (ΔHvap). We present two definitions of "non-volatile OA," one being a global and one a local definition. Based on these definitions, our analysis indicates that a substantial fraction of the organic aerosol is comprised of non-volatile components that will not evaporate under any atmospheric conditions, on the order of 50–80% when the most realistic ΔHvap assumptions are considered. The sensitivity of the total OA mass to dilution and ambient changes in temperature has been assessed for the various ΔHvap assumptions. The temperature sensitivity is relatively independent of the particular ΔHvap assumptions whereas dilution sensitivity is found to be greatest for the low (ΔHvap = 50 kJ/mol) and lowest for the high (ΔHvap = 150 kJ/mol) assumptions. This difference arises from the high ΔHvap assumptions yielding volatility distributions with a greater fraction of non-volatile material than the low ΔHvap assumptions. If the observations are fit using a 1 or 2-component model the sensitivity of the OA to dilution is unrealistically high. An empirical method introduced by Faulhaber et al. (2009) has also been used to independently estimate a volatility distribution for the ambient OA and is found to give results consistent with the high and variable ΔHvap assumptions. Our results also show that the amount of semivolatile gas-phase organics in equilibrium with the OA could range from ~20% to 400% of the OA mass, with smaller values generally corresponding to the higher ΔHvap assumptions. The volatility of various OA components determined from factor analysis of AMS spectra has also been assessed. In general, it is found that the fraction of non-volatile material follows the pattern: biomass burning OA < hydrocarbon-like OA < semivolatile oxygenated OA < low-volatility oxygenated OA. Correspondingly, the sensitivity to dilution and the estimated amount of semivolatile gas-phase material for the OA factors follows the reverse order. Primary OA has a substantial semivolatile fraction, in agreement with previous results, while the non-volatile fraction appears to be dominated by oxygenated OA produced by atmospheric aging. The overall OA volatility is thus controlled by the relative contribution of each aerosol type to the total OA burden. Finally, the model/measurement comparison appears to require OA having an evaporation coefficient (γe) substantially greater than 10−2; at this point it is not possible to place firmer constraints on γe based on the observations.

scholarly journals Water vapour foreign-continuum absorption in near-infrared windows from laboratory measurements

2012 ◽  
Vol 370 (1968) ◽  
pp. 2557-2577 ◽  
Author(s):  
Igor V. Ptashnik ◽  
Robert A. McPheat ◽  
Keith P. Shine ◽  
Kevin M. Smith ◽  
R. Gary Williams
Keyword(s):  
Water Vapour ◽  
Near Infrared ◽  
Prediction Models ◽  
Weather Prediction ◽  
Pair Interaction ◽  
Atmospheric Conditions ◽  
Laboratory Measurements ◽  
Atmospheric Absorption ◽  
Clear Sky ◽  
Long Time

For a long time, it has been believed that atmospheric absorption of radiation within wavelength regions of relatively high infrared transmittance (so-called ‘windows’) was dominated by the water vapour self-continuum, that is, spectrally smooth absorption caused by H 2 O−H 2 O pair interaction. Absorption due to the foreign continuum (i.e. caused mostly by H 2 O−N 2 bimolecular absorption in the Earth's atmosphere) was considered to be negligible in the windows. We report new retrievals of the water vapour foreign continuum from high-resolution laboratory measurements at temperatures between 350 and 430 K in four near-infrared windows between 1.1 and 5 μm (9000–2000 cm −1 ). Our results indicate that the foreign continuum in these windows has a very weak temperature dependence and is typically between one and two orders of magnitude stronger than that given in representations of the continuum currently used in many climate and weather prediction models. This indicates that absorption owing to the foreign continuum may be comparable to the self-continuum under atmospheric conditions in the investigated windows. The calculated global-average clear-sky atmospheric absorption of solar radiation is increased by approximately 0.46 W m −2 (or 0.6% of the total clear-sky absorption) by using these new measurements when compared with calculations applying the widely used MTCKD (Mlawer–Tobin–Clough–Kneizys–Davies) foreign-continuum model.

Gas-Phase Spectroscopy of the Unstable AcetonitrileN-Oxide Molecule, CH3CNO

2001 ◽  
Vol 105 (8) ◽  
pp. 1244-1253 ◽  
Author(s):  
Tibor Pasinszki ◽  
Nicholas P. C. Westwood
Keyword(s):  
Gas Phase ◽  
Oxide Molecule ◽  
Gas Phase Spectroscopy
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