J/A+A/568/A58ivo://CDS.VizieR/J/A+A/568/A58doi:10.26093/cds/vizier.35680058CDSHaykal I.Carvajal M.Tercero B.Kleiner I.Lopez A.Cernicharo J.,Motiyenko R.A.Huet T.R.Guillemin J.C.Margules L.2015-01-19T08:49:48Z2014-08-20T12:17:40ZCDS support team

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

cds-question@unistra.frinterstellar-mediumatomic-physicsradio-astronomyAn astronomical survey of interstellar molecular clouds needs a previous analysis of the spectra in the microwave and sub-mm energy range of organic molecules to be able to identify them. We obtained very accurate spectroscopic constants in a comprehensive laboratory analysis of rotational spectra. These constants can be used to predict the transitions frequencies very precisely that were not measured in the laboratory. We present the experimental study and its theoretical analysis for two ^13^C-methyl formate isotopologues to detect these two isotopologues for the first time in their excited torsional states, which lie at 130/cm (200K) in Orion-KL. New spectra of HCO-O-^13^CH_3_ (^13^C_2_) methyl formate were recorded with the mm- and submm-wave spectrometer in Lille from 50 to 940GHz. A global fit for v_t_=0 and 1 was accomplished with the BELGI program to reproduce the experimental spectra with greater accuracy. We analysed 5728 and 2881 new lines for v_t_=0 and 1 for HCOO^13^CH_3_. These new lines were globally fitted with 846 previously published lines for v_t_=0. In consequence, 52 parameters of the RAM Hamiltonian were accurately determined and the value of the barrier height (V_3_=369.93168(395)/cm) was improved. We report the detection of the first excited torsional states (v_t_=1) in Orion-KL for the ^13^C_2_ and ^13^C_1_ methyl formate based on the present analysis and previously published data. We provide column densities, isotopic abundances, and vibrational temperatures for these species. Following this work, accurate prediction can be provided. This permits detecting 135 features of the first excited torsional states of ^13^C-methyl formate isotopologues in Orion-KL in the 80-280GHz frequency range, without missing lines.2014A&A...568A..58Hhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/568/A58CatalogResearchIsServedByTAP VizieR generic servicerelated-toJ/A+A/500/1109 : Rotational spectrum of HCOO^13^CH_3_ (Carvajal+, 2009)J/ApJ/714/1120 : Rotational spectrum and DCOOCH_3_ in Orion (Margules+, 2010)J/ApJS/190/315 : Rotational spectrum of H^13^COOCH_3_ (Carvajal+, 2010)J/A+A/538/A119 : ^18^O-methyl formate (HCO^18^OCH_3_) spectrum (Tercero+ 2012)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/568/A58https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/568/A58http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/568/A58https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/568/A58https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/568/A58http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/568/A58GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapRadiodefaultJ/A+A/568/A58/tablea1* ^13^C_2_-Methylformate HCO-O-^13^CH_3_ datarecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintvt'[0/1] Vibrational state (upper state)phys.mol.qnintJ'[1/63] Quantum number (upper state)phys.atmol.qnintKa'[-35/35] Quantum number (upper state) (1)phys.mol.qnintKc'[0/63] Quantum number (upper state)phys.mol.qnintp'[+/-] Parity (upper state) (2)phys.atmol.paritycharvt''[0/1] Vibrational state (lower state)phys.mol.qnintJ''[0/62] Quantum number (lower state)phys.atmol.qnintKa''[-35/35] Quantum number (lower state) (1)phys.mol.qnintKc''[0/62] Quantum number (lower state)phys.mol.qnintp''[+/-] Parity (lower state) (2)phys.atmol.paritycharFreq[4663/937370] Observed vt=0 and 1 microwave transitionsMHzem.freqdoublee_Freq[5/200] Uncertainty of FreqkHzstat.errorintFreqCCalculated line frequencyMHzem.freq;spect.line;meta.modelleddoublee_FreqCUncertainty of FreqCkHzstat.errorintO-C[-0.3/0.3] Residual (Observed minus calculated frequencies value)MHzstat.fit.residualfloatS[0/201.3] Calculated line strengths (S(i->f)); see section 4D**2spect.line.intensityfloatElow[0/1111] Lower energy levels for ^13^C_2_-methyl formate (HCOO^13^CH_3_) (3)cm**-1phys.energy;stat.mindoubleRefReference of the data (AA09=Carvajal et al., 2009, Cat. J/A+A/500/1109 or NEW=this work)meta.ref;pos.framecharBl[B] B: blended linesmeta.codechar