J/ApJS/216/3ivo://CDS.VizieR/J/ApJS/216/3doi:10.26093/cds/vizier.22160003CDSTejeda G.Carmona-Novillo E.Moreno E.Fernandez J.M.Hernandez M.I.,Montero S.2015-03-28T17:00:24Z2015-03-02T13:05:40ZCDS support team

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

cds-question@unistra.fratomic-physicsState-to-state rate coefficients for ortho-H_2_O:He and para-H_2_O:He inelastic collisions in the 20-120K thermal range are investigated by means of an improved experimental procedure. This procedure is based on the use of a kinetic master equation (MEQ) which describes the evolution of populations of H_2_O rotational levels along a supersonic jet of H_2_O highly diluted in helium. The MEQ is expressed in terms of experimental observables and rate coefficients for H_2_O:He inelastic collisions. The primary experimental observables are the local number density and the populations of the rotational energy levels of H_2_O, quantities which are determined along the jet with unprecedented accuracy by means of Raman spectroscopy with high space resolution. Sets of rate coefficients from the literature and from present close-coupling calculations using two different potential energy surfaces (PESs) have been tested against the experiment. The Green et al. (VI/59) rate coefficients are up to 50% too low compared to the experiment, while most rates calculated here from the Hodges et al. (2002JChPh.116.1397H) PES and the Patkowski et al. (2002, JMoSt TEOCHEM, 591, 231) PES are much closer to the experimental values. Experimental rates with an estimated accuracy on the order of 10% have been obtained for ortho-H_2_O:He and para-H_2_O:He inelastic collisions between 20 and 120K by scaling and averaging the theoretical rates to the experiment.2015ApJS..216....3Thttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJS/216/3CatalogResearchIsServedByTAP VizieR generic servicerelated-toVI/59 : COLLISIONAL EXCITATION RATES FOR INTERSTELLAR WATER (Green+, 1993)J/A+A/492/257 : Collisional excitation of water in warm media (Faure+, 2008)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJS/216/3https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJS/216/3http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJS/216/3https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJS/216/3https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJS/216/3http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJS/216/3GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapdefaultJ/ApJS/216/3/table3Calculated and experiment-scaled k_l->i rates for ortho and para-H2O:He collisionsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintTypeH_2_O molecule type ("ortho" or "para")meta.code;phys.atmol.transitioncharl[2/13] Initial rotational state (G1)meta.idinti[1/8] Final rotational state (G1)meta.idintJl[1/5] Rotational quantum number of initial statephys.atmol.qnintJi[0/4] Rotational quantum number of final statephys.atmol.qnintEl-Ei[1.9/384] Approximate collision energy gapcm**-1stat.fit.omc;phys.energyfloatTt[20/120] Translational temperatureKphys.temperatureintGratCCalculated G-rate from G-PES (1)1e-14cm**3.s**-1arith.rate;phys.atmol.collisionalintHratCCalculated H-rate from H-PES (1)1e-14cm**3.s**-1arith.rate;phys.atmol.collisionalintPratCCalculated P-rate from P-PES (1)1e-14cm**3.s**-1arith.rate;phys.atmol.collisionalintGratEExperiment-scaled G-rate from G-PES (2)1e-14cm**3.s**-1arith.rate;phys.atmol.collisionalintHratEExperiment-scaled H-rate from H-PES (2)1e-14cm**3.s**-1arith.rate;phys.atmol.collisionalintPratEExperiment-scaled P-rate from P-PES (2)1e-14cm**3.s**-1arith.rate;phys.atmol.collisionalintkSE[0/3512] Averaged experimental rate (2)1e-14cm**3.s**-1arith.rate;phys.atmol.collisionalinte_kSE[1/265] Estimated 1{sigma} uncertainty in kSE (3)1e-14cm**3.s**-1stat.errorintJ/ApJS/216/3/table4Experimental k^SE^_l->i_ deexcitation rates for ortho and para-H2O:He collisionrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintTypeMolecule type (ortho or para)meta.code;phys.atmol.transitioncharl[2/13] Initial rotational state (G1)meta.idinti[1/8] Final rotational state (G1)meta.idintJl[1/5] Rotational quantum number of initial statephys.atmol.qnintJi[0/4] Rotational quantum number of final statephys.atmol.qnintEl-Ei[1.9/384] Approximate collision energy gapcm**-1stat.fit.omc;phys.energyfloatE20Experimental k^SE^_l->i_ rate at 20K (1)1e-14cm**3.s**-1arith.rateinte_E20The 1{sigma} uncertainty in E20 (2)1e-14cm**3.s**-1stat.errorintE40Experimental k^SE^_l->i_ rate at 40K (1)1e-14cm**3.s**-1arith.rateinte_E40The 1{sigma} uncertainty in E40 (2)1e-14cm**3.s**-1stat.errorintE60Experimental k^SE^_l->i_ rate at 60K (1)1e-14cm**3.s**-1arith.rateinte_E60The 1{sigma} uncertainty in E60 (2)1e-14cm**3.s**-1stat.errorintE80Experimental k^SE^_l->i_ rate at 80K (1)1e-14cm**3.s**-1arith.rateinte_E80The 1{sigma} uncertainty in E80 (2)1e-14cm**3.s**-1stat.errorintE100Experimental k^SE^_l->i_ rate at 100K (1)1e-14cm**3.s**-1arith.rateinte_E100The 1{sigma} uncertainty in E100 (2)1e-14cm**3.s**-1stat.errorintE120Experimental k^SE^_l->i_ rate at 120K (1)1e-14cm**3.s**-1arith.rateinte_E120The 1{sigma} uncertainty in E120 (2)1e-14cm**3.s**-1stat.errorint