J/A+A/642/A29ivo://CDS.VizieR/J/A+A/642/A29doi:10.26093/cds/vizier.36420029CDSMotiyenko R.A.Belloche AGarrod R.T.Margules L.Mueller H.S.P.,Menten K.M.Guillemin J.-C.2020-12-07T11:40:57Z2020-10-01T08:25:40ZCDS support team

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

cds-question@unistra.fratomic-physicsThioformamide NH_2_CHS is a sulfur-bearing analog of formamide NH_2_CHO. The latter was detected in the interstellar medium back in the 1970s. Most of the sulfur-containing molecules detected in the interstellar medium are analogs of corresponding oxygen-containing compounds. Therefore, thioformamide is an interesting candidate for a search in the interstellar medium. A previous study of the rotational spectrum of thioformamide was limited to frequencies below 70GHz and to transitions with J<=3. The aim of this study is to provide accurate spectroscopic parameters and rotational transition frequencies for thioformamide to enable astronomical searches for this molecule using radio telescope arrays at millimeter wavelengths. The rotational spectrum of thioformamide was measured and analyzed in the frequency range 150 to 660GHz using the Lille spectrometer. We searched for thioformamide toward the high-mass star-forming region Sagittarius (Sgr) B2(N) using the ReMoCA spectral line survey carried out with the Atacama Large Millimeter/submillimeter Array (ALMA). Accurate rigid rotor and centrifugal distortion constants were obtained from the analysis of the ground state of parent, ^34^S, ^13^C, and ^15^N singly substituted isotopic species of thioformamide. In addition, for the parent isotopolog, the lowest two excited vibrational states, v_12_=1 and v_9_=1, were analyzed using a model that takes Coriolis coupling into account. Thioformamide was not detected toward the hot cores Sgr B2(N1S) and Sgr B2(N2). The sensitive upper limits indicate that thioformamide is nearly three orders of magnitude at least less abundant than formamide. This is markedly different from methanethiol, which is only about two orders of magnitude less abundant than methanol in both sources. The different behavior shown by methanethiol versus thioformamide may be caused by the preferential formation of the latter (on grains) at late times and low temperatures, when CS abundances are depressed. This reduces the thioformamide-to- formamide ratio, because the HCS radical is not as readily available under these conditions.2020A&A...642A..29Mhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/642/A29CatalogResearchIsServedByTAP VizieR generic servicerelated-toJ/A+A/493/565 : Deuterated and ^15^N ethyl cyanides (Margules+, 2009)J/A+A/538/A51 : Rotational spectrum of CH_3_CH(NH_2_)CN (Mollendal+, 2012)J/A+A/538/A119 : ^18^O-methyl formate (HCO^18^OCH_3_) spectrum (Tercero+ 2013)J/A+A/543/A46 : Submillimeter spectrum of HCOOCD_2_H (Coudert+, 2012)J/A+A/543/A135 : New analysis of ^13^C-CH_3_CH_2_CN up to 1THz (Richard+, 2012)J/A+A/544/A82 : Diisocyanomethane rotational spectroscopy (Motiyenko+, 2012)J/A+A/548/A71 : Spectroscopy and ISM detection of formamide (Motiyenko+, 2012)J/A+A/549/A96 : mm and sub-mm spectra of 13C-glycolaldehydes (Haykal+, 2013)J/A+A/559/A44 : Rotational spectrum of MAAN (CH_2_NCH_2_CN) (Motiyenko+, 2013)J/A+A/563/A137 : THz spectrum of methylamine (Motiyenko+, 2014)J/A+A/568/A58 : HCOO^13^CH_3_ rotational spectrum (Haykal+, 2014)J/A+A/579/A46 : Mono-^13^C acetaldehydes mm/submm wave spectraJ/A+A/587/A152 : Rotational spectrum of ^13^C methylamine (Motiyenko+, 2016)J/A+A/590/A93 : Doubly ^13^C-substituted ethyl cyanide (Margules+, 2016)J/A+A/592/A43 : Millimeter wave spectra of carbonyl cyanide (Bteich+, 2016)J/A+A/601/A2 : Triple ^13^C-substituted ethyl cyanide (Pienkina, 2017)J/A+A/601/A49 : CH_3_NHCHO rotational spectroscopy (Belloche+, 2017)J/A+A/601/A50 : Sub-millimeter spectra of 2-hydroxyacetonitrileJ/A+A/610/A44 : Ethyl isocyanide submillimeter wave spectroscopyJ/A+A/619/A92 : Laboratory analysis of methylketene (Bermuez+, 2018)J/A+A/623/A162 : Spectroscopy of CH2(CN)2 and CNCH2CN (Motiyenko+, 2019)J/A+A/624/A70 : Acetaldehyde CH_2_DCOH and CH_3_COD (Coudert+, 2019)J/A+A/638/A3 : Cyanoketene (NC-CH=C=O) mm wave spectroscopy (Margules+, 2020)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/642/A29https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/642/A29http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/642/A29https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/642/A29https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/642/A29http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/642/A29GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapdefaultJ/A+A/642/A29/tablea1Assigned and fitted rotational transitions of the ground state of thioformamide (parent isotopolog)recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintJ'Upper J quantum numberinstr.det.qe;stat.maxintKa'Upper Ka quantum numberphys.mol.qn;stat.maxintKc'Upper Kc quantum numberphys.mol.qn;stat.maxintJ"Lower J quantum numberinstr.det.qe;stat.minintKa"Lower Ka quantum numberphys.mol.qn;stat.minintKc"Lower Kc quantum numberphys.mol.qn;stat.minintFreqMeasured transition frequencyMHzem.freq;phys.atmol.transitiondoubleO-CResidual of the fitMHzstat.fit.residual;stat.fit.param;meta.modelledfloatUncUncertainty of measurementsMHzstat.errorfloatRelI? Relative intensity for blended line componentsspect.line.intensity;arith.ratiofloatnullableJ/A+A/642/A29/tablea2Predicted rotational transitions of the v=0 state of thioformamide at T=300KKa"Lower Ka quantum numberphys.mol.qn;stat.minintKc"Lower Kc quantum numberphys.mol.qn;stat.minintFreqCalculated transition frequencyMHzem.freq;phys.atmol.transition;meta.modelleddoubleO-CUncertainty of pcalculated transition frequencyMHzstat.error;em.freq;phys.atmol.transitionfloatlogIntBase 10 logarithm of the integrated intensitylog(nm**2.MHz)spect.line.intensityfloatEloThe energy of the lower statecm**-1phys.energy;phys.atmol.leveldoublerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintJ'Upper J quantum numberinstr.det.qe;stat.maxintKa'Upper Ka quantum numberphys.mol.qn;stat.maxintKc'Upper Kc quantum numberphys.mol.qn;stat.maxintJ"Lower J quantum numberinstr.det.qe;stat.minint