J/A+A/644/A102ivo://CDS.VizieR/J/A+A/644/A102doi:10.26093/cds/vizier.36440102CDSJabri A.Tercero B.Margules L.Motiyenko R.A.Alekseev E.A.,Kleiner I.Cernicharo J.Guillemin J.-C.2021-02-19T06:37:57Z2020-12-07T08:39:47ZCDS support team

CDS, Observatoire de Strasbourg, 11 rue de l'Universite, F-67000 Strasbourg, France

cds-question@unistra.frinterstellar-mediumradio-sourceschemical-abundancesatomic-physicsS-methyl thioformate CH_3_SC(O)H is a monosulfur derivative of methyl formate, a relatively abundant component of the interstellar medium (ISM). S-methyl thioformate being, thermodynamically,the most stable isomer, it can be reasonably proposed for detection in the ISM. This work aims to experimentally study and theoretically analyze the ground and first torsional excited states for CH_3_SC(O)H in a large spectral range for astrophysical use. S-methyl thioformate was synthesized as a result of a reaction of methyl mercaptan with acetic-formic anhydride. The millimeter-wave spectrum was then recorded for the first time from 150 to 660GHz with the solid-state-based spectrometer at Lille. A set of 3545 lines is determined and combined with 54 previously measured lines in the microwave region, belonging to ground state vt=0 as well as 1391 transitions in the first excited state of torsion v18=1. Some 164 lines were also assigned to vt18=2 for the A-species. A global fit was performed using the BELGI-Cs code taking into account the large splitting of A and E lines due to methyl internal rotation motion with a relatively low barrier, V3=127.4846(15)cm^-1^. Using our spectroscopy work, a deep search of S-methyl thioformate was carried out in the IRAM 30m and ALMA data of different high-mass star-forming regions (Orion KL and Sgr B2). We derived an upper limit to the CH_3_SC(O)H column density in these regions.2020A&A...644A.102Jhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/644/A102CatalogResearchIsServedByTAP VizieR generic servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/644/A102https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/644/A102http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/644/A102https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/644/A102https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/644/A102http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/644/A102GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapRadiodefaultJ/A+A/644/A102/tablea1Observed line frequencies and line strengthsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintvt'Upper state torsional quantum numberphys.mol.qnintJ'Upper state rotational quantum numberphys.mol.qnintKa'Upper state projection of J on the a-principal axisphys.mol.qnintKc'Upper state projection of J on the c-principal axisphys.mol.qnintP'Upper state "parity" quantum number for A speciesphys.atmol.paritycharvt"lower state torsional quantum numberphys.mol.qnintJ"lower state rotational quantum numberphys.mol.qnintKa"Lower state projection of J on the a-principal axisphys.mol.qnintKc"Lower state projection of J on the c-principal axisphys.mol.qnintP"Lower state "parity" quantum number for A speciesphys.atmol.paritycharSymmetrySymmetry species (A or E) for the internal rotormeta.codecharObsObserved transition frequency in the laboratoryMHzem.freqdoubleUncExperimental uncertaintykHzstat.errorintCalcCalculated frequencyMHzem.freq;meta.modelleddoubleObs-CalcObserved-Calculated residualsMHzem.freqfloatEupUpper state energycm**-1phys.energydoubleElowLower state energycm**-1phys.energydoubleSmu2Line Strength (in Debye^2^ unit)D**2spect.line.intensitydouble