scholarly journals Laboratory spectroscopic study of the 15N isotopomers of cyanamide, H2NCN, and a search for them toward IRAS 16293−2422 B

2019 ◽  
Vol 623 ◽  
pp. A93 ◽  
Author(s):  
Audrey Coutens ◽  
Olena Zakharenko ◽  
Frank Lewen ◽  
Jes K. Jørgensen ◽  
Stephan Schlemmer ◽  
...  
Keyword(s):  
Laboratory Data ◽  
Natural Isotopic Composition ◽  
Interstellar Molecules ◽  
Spectroscopic Parameters ◽  
Rotational Spectra ◽  
Isotopic Species ◽  
Upper Limits ◽  
Solar Type ◽  
Line Survey

Context. Cyanamide is one of the few interstellar molecules containing two chemically different N atoms. It was detected recently toward the solar-type protostar IRAS 16293−2422 B together with H2N13CN and HDNCN in the course of the Atacama Large Millimeter/submillimeter Array (ALMA) Protostellar Interferometric Line Survey (PILS). The detection of the 15N isotopomers or the determination of upper limits to their column densities was hampered by the lack of accurate laboratory data at the frequencies of the survey. Aims. We wanted to determine spectroscopic parameters of the 15N isotopomers of cyanamide that are accurate enough for predictions well into the submillimeter region and to search for them in the PILS data. Methods. We investigated the laboratory rotational spectra of H215NCN and H2NC15N in the selected region between 192 and 507 GHz employing a cyanamide sample in natural isotopic composition. Additionally, we recorded transitions of H2N13CN. Results. We obtained new or improved spectroscopic parameters for the three isotopic species. Neither of the 15N isotopomers of cyanamide were detected unambiguously in the PILS data. Two relatively clean lines can be tentatively assigned to H215NCN. If confirmed, their column densities would imply a low 14N/15N ratio for cyanamide toward this source. Conclusions. The resulting line lists should be accurate enough for observations up to about 1 THz. More sensitive observations, potentially at different frequencies, may eventually lead to the astronomical detection of these isotopic species.

scholarly journals Laboratory spectroscopic study of isotopic thioformaldehyde, H2CS, and determination of its equilibrium structure

2019 ◽  
Vol 621 ◽  
pp. A143 ◽  
Author(s):  
Holger S. P. Müller ◽  
Atsuko Maeda ◽  
Sven Thorwirth ◽  
Frank Lewen ◽  
Stephan Schlemmer ◽  
...  
Keyword(s):  
Structural Parameters ◽  
Laboratory Data ◽  
Abundant Species ◽  
Equilibrium Structure ◽  
Natural Isotopic Composition ◽  
Spectroscopic Parameters ◽  
Rotational Spectra ◽  
Isotopic Species ◽  
Semi Empirical

Context. Thioformaldehyde is an abundant molecule in various regions of the interstellar medium. However, available laboratory data limit the accuracies of calculated transition frequencies in the submillimeter region, in particular for minor isotopic species. Aims. We aim to determine spectroscopic parameters of isotopologs of H2CS that are accurate enough for predictions well into the submillimeter region. Methods. We investigated the laboratory rotational spectra of numerous isotopic species in natural isotopic composition almost continuously between 110 and 377 GHz. Individual lines were studied for most species in two frequency regions between 566 and 930 GHz. Further data were obtained for the three most abundant species in the 1290−1390 GHz region. Results. New or improved spectroscopic parameters were determined for seven isotopic species. Quantum-chemical calculations were carried out to evaluate the differences between ground state and equilibrium rotational parameters to derive semi-empirical equilibrium structural parameters. Conclusions. The spectroscopic parameters are accurate enough for predictions well above 1 THz with the exception of H213C34S where the predictions should be reliable to around 700 GHz.

Rotational spectra of rare isotopic species of bromofluoromethane: Determination of the equilibrium structure from ab initio calculations and microwave spectroscopy

2007 ◽  
Vol 127 (16) ◽  
pp. 164302 ◽  
Author(s):  
Cristina Puzzarini ◽  
Gabriele Cazzoli ◽  
Agostino Baldacci ◽  
Alessandro Baldan ◽  
Christine Michauk ◽  
...  
Keyword(s):  
Ab Initio Calculations ◽  
Ab Initio ◽  
Equilibrium Structure ◽  
Microwave Spectroscopy ◽  
Rotational Spectra ◽  
Isotopic Species

scholarly journals Determination of Rotational Parameters of CH3CN, CD3CN and their Different Isotopic Species in the Ground and v4= 1 States

2009 ◽  
Vol 6 (2) ◽  
pp. 577-593
Author(s):  
Masoud Motamedi ◽  
Parinaz Moradi
Keyword(s):  
Millimeter Wave ◽  
Rotational Spectra ◽  
Isotopic Species ◽  
Symmetric Top Molecules ◽  
First Time

The millimeter-wave rotational spectra of the symmetric top molecules CH3CN,13CH3CN, CH313CN, CH3C15N, CD3CN ,13CD3CN, CD313CN and CD3C15N have been investigated again in their ground and v4= 1 states. The analysis of spectra and fitting the frequencies in these states give rotational parameters with higher accuracy compare with previous works. The parameter HJ= -0.107(96) mHz was determined for CH3C15N for the first time.

scholarly journals Laboratory rotational spectroscopy of isotopic acetone, CH313C(O)CH3 and 13CH3C(O)CH3, and astronomical search in Sagittarius B2(N2)

2019 ◽  
Vol 629 ◽  
pp. A72 ◽  
Author(s):  
Matthias H. Ordu ◽  
Oliver Zingsheim ◽  
Arnaud Belloche ◽  
Frank Lewen ◽  
Robin T. Garrod ◽  
...  
Keyword(s):  
Excited States ◽  
Isotopic Ratio ◽  
Spectral Lines ◽  
Emission Lines ◽  
Rotational Spectrum ◽  
Rotational Spectra ◽  
Terahertz Region ◽  
Isotopic Species ◽  
Molecular Core ◽  
Line Survey

Context. Spectral lines of minor isotopic species of molecules that are abundant in space may also be detectable. Their respective isotopic ratios may provide clues about the formation of these molecules. Emission lines of acetone in the hot molecular core Sagittarius B2(N2) are strong enough to warrant a search for its singly substituted 13C isotopologs. Aims. We want to study the rotational spectra of CH313C(O)CH3 and 13CH3C(O)CH3 and search for them in Sagittarius B2(N2). Methods. We investigated the laboratory rotational spectrum of isotopically enriched CH313C(O)CH3 between 40 GHz and 910 GHz and of acetone between 36 GHz and 910 GHz in order to study 13CH3C(O)CH3 in natural isotopic composition. In addition, we searched for emission lines produced by these species in a molecular line survey of Sagittarius B2(N) carried out with the Atacama Large Millimeter/submillimeter Array (ALMA). Discrepancies between predictions of the main isotopic species and the ALMA spectrum prompted us to revisit the rotational spectrum of this isotopolog. Results. We assigned 9711 new transitions of CH313C(O)CH3 and 63 new transitions of 13CH3C(O)CH3 in the laboratory spectra. More than 1000 additional transitions were assigned for the main isotopic species. We modeled the ground state data of all three isotopologs satisfactorily with the ERHAM program. We find that models of the torsionally excited states v12 = 1 and v17 = 1 of CH3C(O)CH3 improve only marginally. No transitrrrion of CH313C(O)CH3 is clearly detected toward the hot molecular core Sgr B2(N2). However, we report a tentative detection of 13CH3C(O)CH3 with a 12C/13C isotopic ratio of 27 that is consistent with the ratio previously measured for alcohols in this source. Several dozens of transitions of both torsional states of the main isotopolog are detected as well. Conclusion. Our predictions of CH313C(O)CH3 and CH3C(O)CH3 are reliable into the terahertz region. The spectrum of 13CH3C(O)CH3 should be revisited in the laboratory with an enriched sample. The torsionally excited states v12 = 1 and v17 = 1 of CH3C(O)CH3 were not reproduced satisfactorily in our models. Nevertheless, transitions pertaining to both states could be identified unambiguously in Sagittarius B2(N2).

Impact of sulfate on the solubility of Tc(IV) in acidic to hyperalkaline aqueous reducing systems

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Sarah B. Duckworth ◽  
Xavier Gaona ◽  
Alexander Baumann ◽  
Kathy Dardenne ◽  
Jörg Rothe ◽  
...  
Keyword(s):  
Solid Phase ◽  
Correction Factors ◽  
Mixed Salt ◽  
Ph Values ◽  
Reducing Conditions ◽  
Upper Limits ◽  
Salt Systems ◽  
Amorphous Character ◽  
Good Agreement

Abstract The solubility of 99Tc(IV) was investigated from undersaturation conditions in NaCl–Na2SO4 (0.3 M ≤ I ≤ 5.0 M), MgCl2–MgSO4 (I = 13.5 M) and CaCl2–CaSO4 (I = 13.5 M) systems with 0.001 M ≤ [SO4 2−]tot ≤ 1.0 M and 1 ≤ pH m  ≤ 12 (with pH m  = −log[H+], in molal units). Reducing conditions were set by either Sn(II) or Fe(0). Special efforts were dedicated to accurately characterize the correction factors A m required for the determination of pH m from the experimentally measured pH values in the mixed salt systems investigated, with pH m  = pHexp + A m . The combination of (pe + pH m ) measurements with Pourbaix diagrams of Tc suggests that technetium is present in its +IV redox state. This hypothesis is confirmed by XANES, which unambiguously shows the predominance of Tc(IV) both in the aqueous and solid phases of selected solubility samples. XRD and SEM–EDS support the amorphous character of the solid phase controlling the solubility of Tc(IV). EXAFS data confirm the predominance of TcO2(am, hyd) at pH m  > 1.5, whereas the formation of a Tc(IV)–O–Cl solid phase is hinted at lower pHm values in concentrated NaCl–Na2SO4 systems with ≈5 M NaCl. Solubility data collected in sulfate-containing systems are generally in good agreement with previous solubility studies conducted in sulfate-free NaCl, MgCl2 and CaCl2 solutions of analogous ionic strength. Although the complexation of Tc(IV) with sulfate cannot be completely ruled out, these results strongly support that, if occurring, complexation must be weak and has no significant impact on the solubility of Tc(IV) in dilute up to highly saline media. Solubility upper-limits determined in this work can be used for source term estimations including the effect of sulfate in a variety of geochemical conditions relevant in the context of nuclear waste disposal.

scholarly journals Use of the Accusport semi-automated analyser to determine blood lactate as an aid in the clinical assessment of horses with colic

2001 ◽  
Vol 72 (1) ◽  
Author(s):  
M.L. Schulman ◽  
J.P. Nurton ◽  
A.J. Guthrie
Keyword(s):  
Blood Lactate ◽  
Laboratory Data ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
Tissue Perfusion ◽  
Diagnostic Methods ◽  
Initial Assessment ◽  
Clinically Normal ◽  
Case Outcome

The most useful diagnostic methods in the initial evaluation of horses with colic assess the morphological and functional status of the gastrointestinal tract and cardiovascular status. This evaluation is best achieved using a combination of clinical and laboratory data. Blood lactate concentration (BL) is one of these variables. BL rises mainly due to poor tissue perfusion and anaerobic glycolysis associated with shock, providing an indicator of both the severity of disease and its prognosis. A hand-held lactate meter, Accusport, provides a rapid (60 seconds), inexpensive dry-chemical-based determination of BL. This trial evaluated the Accusport's ability to provide BL data as an adjunct to the initial clinical evaluation of horses with colic. The accuracy of the Accusport was tested by evaluation of its interchangeability with the benchmark enzymatic kit evaluation of BL in a trial using data collected firstly from 10 clinically normal control horses and subsequently from 48 horses presented with signs of colic. The BL values were recorded together with the clinical variables of heart rate (HR), capillary refill time (CRT), haematocrit (Hct), and pain character and severity on the initial assessment of the colic horses. Information regarding choice of therapeutic management (medical or surgical) and eventual case outcome (full recovery or died/euthanased) was recorded. The Accusport was found to be interchangeable with the enzymatic kit for recording BL values in colic horses with BL <10 mmol/ , which is within the BL range associated with survival. The interchangeability of an additional, laboratory-based wet chemical assay for BL, the Stat 7 was simultaneously evaluated for the colic and control horses. The Stat 7 was found to be interchangeable with the enzymatic kit for BL determination of colic horses. No linear associations between BL values with HR, CRT, Hct or pain assessment were observed. No relationship with either selection of therapeutic method or eventual case outcome was observed. All horses with BL >8 mmol/ died or were euthanased.

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