J/A+A/531/A103ivo://CDS.VizieR/J/A+A/531/A103doi:10.26093/cds/vizier.35310103CDSCernicharo J.Spielfiedel A.Balanca C.Dayou F.Senent M.-L.,Feautrier N.Faure A.Cressiot-Vincent L.Wiesenfeld L.Pardo J.R.2011-08-08T11:16:55Z2011-06-21T08:21:41ZCDS support team

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

cds-question@unistra.fratomic-physicsmolecular-cloudsWe present collisional rate coefficients for SO_2_ with ortho and para molecular hydrogen for the physical conditions prevailing in dark molecular clouds. Rate coefficients for the first 31 rotational levels of this species (energies up to 55K) and for temperatures between 5 and 30K are provided. We have found that these rate coefficients are about ten times more than those previously computed for SO_2_ with helium. We calculated the expected emission of the centimeter wavelength lines of SO_2_. We find that the transition connecting the metastable 2_02_ level with the 111 one is in absorption against the cosmic background for a wide range of densities. The 4_04_-3_13_ line is found to be inverted for densities below a few 10^4^cm^-3^. We observed the 1_11_-2_02_ transition with the 100m Green Bank Telescope towards some dark clouds. The line is observed, as expected, in absorption and provides an abundance of SO_2_ in these objects of a few 10^-10^. The potential use of millimeter lines of SO_2_ as tracers of the physical conditions of dark clouds is discussed.2011A&A...531A.103Chttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/531/A103CatalogResearchIsServedByTAP VizieR generic servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/531/A103https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/531/A103http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/531/A103https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/531/A103https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/531/A103http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/531/A103GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapdefaultJ/A+A/531/A103/table1SO_2_ calculated energy levelsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintLevelLevel numbermeta.idintTransj(Ka,Kc) valuemeta.id;phys.atmol.transitioncharEThis work energy levelcm**-1phys.energy;phys.atmol.levelfloatEJPLJPL energy level (1)cm**-1phys.energy;phys.atmol.levelfloatJ/A+A/531/A103/table5Rate coefficients of SO_2_ in collision with para-H2(j2=0,2) as function of kinetic temperature (opposite nuclear spins of the 2 protons in H_2_)FFinal levelphys.mol.qnintrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintIInitial levelphys.mol.qnintRate(5)Rate coefficient at temperature Tkin=5Kcm**3.s**-1arith.rate;phys.atmol.collisionaldoubleRate(10)Rate coefficient at temperature Tkin=10Kcm**3.s**-1arith.rate;phys.atmol.collisionaldoubleRate(15)Rate coefficient at temperature Tkin=15Kcm**3.s**-1arith.rate;phys.atmol.collisionaldoubleRate(20)Rate coefficient at temperature Tkin=20Kcm**3.s**-1arith.rate;phys.atmol.collisionaldoubleRate(25)Rate coefficient at temperature Tkin=25Kcm**3.s**-1arith.rate;phys.atmol.collisionaldoubleRate(30)Rate coefficient at temperature Tkin=30Kcm**3.s**-1arith.rate;phys.atmol.collisionaldoubleJ/A+A/531/A103/table6Rate coefficients of SO_2_ in collision with ortho-H2(j2=1) as function of kinetic temperature (parallel nuclear spins of the 2 protons in H_2_)recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintIInitial levelphys.mol.qnintFFinal levelphys.mol.qnintRate(5)Rate coefficient at temperature Tkin=5Kcm**3.s**-1arith.rate;phys.atmol.collisionaldoubleRate(10)Rate coefficient at temperature Tkin=10Kcm**3.s**-1arith.rate;phys.atmol.collisionaldoubleRate(15)Rate coefficient at temperature Tkin=15Kcm**3.s**-1arith.rate;phys.atmol.collisionaldoubleRate(20)Rate coefficient at temperature Tkin=20Kcm**3.s**-1arith.rate;phys.atmol.collisionaldoubleRate(25)Rate coefficient at temperature Tkin=25Kcm**3.s**-1arith.rate;phys.atmol.collisionaldoubleRate(30)Rate coefficient at temperature Tkin=30Kcm**3.s**-1arith.rate;phys.atmol.collisionaldouble