J/A+A/472/1029ivo://CDS.VizieR/J/A+A/472/1029doi:10.26093/cds/vizier.34721029CDSFaure A.Crimier N.Ceccarelli C.Valiron P.Wiesenfeld L.Dubernet L.2017-12-05T05:10:31Z2008-03-14T12:24:11ZCDS support team

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

cds-question@unistra.fratomic-physicsThe interpretation of water line emission from existing observations and future HIFI/Herschel data requires a detailed knowledge of collisional rate coefficients. Among all relevant collisional mechanisms, the rotational (de)excitation of H2O by H2 molecules is the process of most interest in interstellar space. We provide rate coefficients for rotational de-excitation among the lowest 45 para and 45 ortho rotational levels of H2O colliding with both para and ortho-H2 in the temperature range 20-2000K. Rate coefficients are calculated on a recent high-accuracy H2O-H2 potential energy surface using quasi-classical trajectory calculations. Trajectories are sampled by a canonical Monte-Carlo procedure. H2 molecules are assumed rotationally thermalized at the kinetic temperature. By comparison with quantum calculations available for low lying levels, classical rates are found to be accurate within a factor of 1-3 for the dominant transitions, that is those with rates larger than a few 10^-12^cm^3^/s. Large velocity gradient modelling shows that the new rates have a significant impact on emission line fluxes and that they should be adopted in any detailed population model of water in warm and hot environments.2007A&A...472.1029Fhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/472/1029CatalogResearchIsServedByTAP VizieR generic servicerelated-toJ/A+A/492/257 : Collisional excitation of water in warm media (Faure+, 2008)J/A+A/493/687 : Rotational excitation of formaldehyde by H2 (Faure+, 2009)J/MNRAS/399/425 : (De)excitation rates of ortho-NH3 and para-NH3 (Faure+, 2009)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/472/1029https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/472/1029http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/472/1029https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/472/1029https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/472/1029http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/472/1029GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapdefaultJ/A+A/472/1029/levelsRotational energy levels of H_2_O in its ground vibrational staterecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintLevel[1/45] Levelmeta.id;phys.atmol.levelintEEnergycm**-1phys.energy;phys.mol.rotationdoubleJJ quantum numbermeta.id;meta.mainintKaKa quantum numberphys.atmol.qnintKcKc quantum numberphys.atmol.qnintStSimbad column added by the CDSphys.atmol.configurationcharJ/A+A/472/1029/h2o_h2De-excitation rates of H_2_O in collision with H_2_iInitial levelphys.atmol.initial;phys.atmol.levelintrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintStSimbad column added by the CDSphys.atmol.configurationcharTransTransition numbermeta.id;meta.mainintfFinal levelphys.atmol.final;phys.atmol.levelintk20Rate coefficient at 20Kcm**3.s**-1arith.ratedoublek100Rate coefficient at 100Kcm**3.s**-1arith.ratedoublek200Rate coefficient at 200Kcm**3.s**-1arith.ratedoublek400Rate coefficient at 400Kcm**3.s**-1arith.ratedoublek800Rate coefficient at 800Kcm**3.s**-1arith.ratedoublek1200Rate coefficient at 1200Kcm**3.s**-1arith.ratedoublek1600Rate coefficient at 1600Kcm**3.s**-1arith.ratedoublek2000Rate coefficient at 2000Kcm**3.s**-1arith.ratedouble