J/A+A/577/A91ivo://CDS.VizieR/J/A+A/577/A91doi:10.26093/cds/vizier.35770091CDSKolesnikova L.Pena I.Alonso J.L.Cernicharo J.Tercero B.Kleiner I.2018-06-11T09:00:04Z2015-05-12T08:00:07ZCDS support team

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

cds-question@unistra.frinterstellar-mediumspectroscopyatomic-physicsThe recent discovery of methyl acetate in Orion KL makes vinyl acetate, CH3-(C=O)-O-CH=CH2, a potential molecule in the interstellar medium.We obtained very accurate spectroscopic constants in a comprehensive laboratory analysis of its rotational spectra which can be used to predict those transition frequencies towards interstellar sources. We present the experimental study and theoretical analysis of the ground torsional state of vinyl acetate in a large spectral range for astrophysical use. The room-temperature rotational spectrum of vinyl acetate has been measured from 125 to 305GHz to provide direct frequencies to the astronomical community. Additional measurements have also been made using a broadband CP-FTMWspectrometer in the region of 6 - 18 GHz. Transition lines, corresponding to the most stable conformer, have been observed and assigned. All the rotational transitions revealed the A-E splitting due to the methyl internal rotation and had to be treated with a specific internal rotation code (BELGI-Cs). We analyzed 2508 transitions up to J"=75 for vt=0 for the most stable conformer of vinyl acetate. The new lines were globally fitted with previously published data and 24 parameters of the Hamiltonian were accurately determined. The spectral features of vinyl acetate were then searched for in Orion KL. Using the whole line survey of Orion KL (80-280GHz) obtained with the IRAM 30m radio telescope we can provide only an upper limit to the column density of vinyl acetate. However, using the ALMA Science Verification data we obtain a tentative detection of this species that will require further search at other frequencies to confirm its presence in this high mass star forming region.2015A&A...577A..91Khttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/577/A91CatalogResearchIsServedByTAP VizieR generic servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/577/A91https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/577/A91http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/577/A91https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/577/A91https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/577/A91http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/577/A91GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapdefaultJ/A+A/577/A91/table1Molecular constants in the {rho}-axis system of vinyl acetate [CH3-(C=O)-O-CH=CH2] obtained from the global fit using program BELGI-CsUnitUnitmeta.unitcharCstConstant label (1)meta.id;stat.fit.paramrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintOperatorOperator (2)phys.atmolValueValue of the parameter from the present fitstat.paramdoublee_ValueError on value (statistical uncertainty)stat.error;stat.valuedoubleJ/A+A/577/A91/table2Assignments, observed frequencies, and calculated frequencies from the RAM fit, line strengths, and energies of the lower and upper energy levels included in the fit with parameters of Table 1recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintJ1[1/75] Upper J quantum numberinstr.det.qe;stat.maxintKa1[-16/16] Upper Ka quantum number (1)phys.mol.qnintKc1[0/75] Upper Kc quantum numberphys.mol.qnintp1[+-] Parity (1)phys.atmol.paritycharJ0[0/75] Lower J quantum numberinstr.det.qe;stat.minintKa0[-15/15] Lower Ka quantum number (1)phys.mol.qnintKc0[0/74] Lower Kc quantum numberphys.mol.qnintp0[+-] Parity (1)phys.atmol.paritycharFreqO[6044/329556] Observed transition frequencyMHzem.freqdoublee_FreqO[5/50] Uncertainty of the experimentally measured linekHzstat.errorintFreqC[6044/329556] Calculated transition frequencyMHzem.freqdoublee_FreqC[0/40] Calculated uncertainty of the transition frequencykHzstat.errorintO-C[-0.24/0.19] Observed minus calculated frequencyMHzstat.fit.residualfloatSmu2[0/175] Calculated line strengthD**2spect.line.intensity;meta.modelledfloatE1[39/452] Upper level energycm**-1phys.energy;phys.atmol.leveldoubleE0[0/407] Lower level energy (2)cm**-1phys.energy;phys.atmol.leveldoubleRef[1/3] Source of the data (3)meta.bibint