Astrochemistry: Synthesis and Modelling

Chapter
Part of the Physical Chemistry in Action book series (PCIA)

Abstract

We discuss models that astrochemists have developed to study the chemical composition of the interstellar medium. These models aim at computing the evolution of the chemical composition of a mixture of gas and dust under astrophysical conditions. These conditions, as well as the geometry and the physical dynamics, have to be adapted to the objects being studied because different classes of objects have very different characteristics (temperatures, densities, UV radiation fields, geometry, history etc); e.g., proto-planetary disks do not have the same characteristics as proto-stellar envelopes. Chemical models are being improved continually thanks to comparisons with observations but also thanks to laboratory and theoretical work in which the individual processes are studied.

Keywords

Rate Coefficient Interstellar Medium Dense Cloud Astrophysical Object Desorption Energy 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Notes

Acknowledgments

V. W.’s research is supported by the French INSU/CNRS program PCMI, the Observatoire Aquitain des Sciences de l’Univers, and the Agence Nationale de Recherche (ANR-JC08−311018: EMA:INC). H.C. thanks the European Research Council (ERC-2010-StG, Grant Agreement no. 259510-KISMOL) and the Netherlands Organisation for Scientific Research (NWO) (VIDI) for financial support. E. H. acknowledges the support of the NSF (US) for his research program in astrochemistry and the support of NASA for his program in exobiology.

References

  1. 1.
    Bergin EA, Philipps TG, Comito C et al (2010) Herschel observations of EXtra-Ordinary sources (HEXOS): the present and future of spectral surveys with Herschel/HIFI. Astron Astrophys 521:L20. doi: 10.1051/0004-6361/201015071 CrossRefGoogle Scholar
  2. 2.
    Dutrey A, Guilloteau S, Ho P (2007) Interferometric spectroimaging of molecular gas in protoplanetary disks. In: Reipurth B, Jewitt D, Keil K (eds) Protostars and planets V. University of Arizona Press, TucsonGoogle Scholar
  3. 3.
    Press WH, Teukolsky SA, Vetterling WT, Flannery BP (1996) Numerical recipes in Fortran 90. Cambridge University Press, New YorkGoogle Scholar
  4. 4.
    Le Bourlot J, Pineau des Forets G, Roueff E, Flower DR (1995) On the uniqueness of the solutions to the chemical rate equations in interstellar clouds: the gas-dust interface. Astron Astrophys 302:870–878Google Scholar
  5. 5.
    Wakelam V, Herbst E, Selsis F, Massacrier G (2006) Chemical sensitivity to the ratio of the cosmic-ray ionization rates of He and H2 in dense clouds. Astron Astrophys 459:813–820. doi: 10.1051/0004-6361:20065472 CrossRefGoogle Scholar
  6. 6.
    Draine BT (2003) Interstellar dust grains. Annu Rev Astron Astr 41:241–289. doi: 10.1146/annurev.astro.41.011802.094840 CrossRefGoogle Scholar
  7. 7.
    Savage BD, Sembach KR (1996) Interstellar abundances from absorption-line observations with the hubble space telescope. Annu Rev Astron Astr 34:279–330. doi: 10.1146/annurev.astro.34.1.279 CrossRefGoogle Scholar
  8. 8.
    Jenkins EB (2009) A unified representation of gas-phase element depletions in the interstellar medium. Astrophys J 700:1299–1348. doi: 10.1088/0004-637X/700/2/1299 CrossRefGoogle Scholar
  9. 9.
    Draine BT (1990) Evolution of interstellar dust. In: The evolution of the interstellar medium; Proceedings of the conference, Berkeley, CA, June 21-23, 1989 (A91-55426 24-90). San Francisco, CA, Astronomical Society of the Pacific, 1990, p. 193–205Google Scholar
  10. 10.
    Draine BT (2009) Interstellar dust models and evolutionary implications. In: Henning T, Grün E, Steinacker J (eds) Cosmic dust – near and far ASP conference series proceedings of a conference held 8–12 September 2008 in Heidelberg, GermanyGoogle Scholar
  11. 11.
    Hily-Blant P, Walmsley M, Pineau Des Forêts G, Flower D (2010) Nitrogen chemistry and depletion in starless cores. Astron Astrophys 513:A41. doi: 10.1051/0004-6361/200913200 CrossRefGoogle Scholar
  12. 12.
    Maret S, Bergin EA, Lada CJ (2006) A low fraction of nitrogen in molecular form in a dark cloud. Nature 442:425–427. doi: 10.1038/nature04919 CrossRefGoogle Scholar
  13. 13.
    van der Tak FFS, Boonman AMS, Braakman R, van Dishoeck EF (2003) Sulfur chemistry in the envelopes of massive young stars. Astron Astrophys 412:133–145. doi: 10.1051/0004-6361:20031409 CrossRefGoogle Scholar
  14. 14.
    Wakelam V, Caselli P, Ceccarelli C, Herbst E, Castets A (2004) Resetting chemical clocks of hot cores based on S-bearing molecules. Astron Astrophys 422:159–169. doi: 10.1051/0004-6361:20047186 CrossRefGoogle Scholar
  15. 15.
    Sofia UJ, Cardelli JA, Savage BD (1994) The abundant elements in interstellar dust. Astrophys J 430:650–666. doi: 10.1086/174438 CrossRefGoogle Scholar
  16. 16.
    Wakelam V, Herbst E, Le Bourlot J, Hersant F, Selsis F, Guilloteau S (2010) Sensitivity analyses of dense cloud chemical models. Astron Astrophys 517:A21. doi: 10.1051/0004-6361/200913856 CrossRefGoogle Scholar
  17. 17.
    Hassel GE, Herbst E, Bergin EA (2010) Beyond the pseudo-time-dependent approach: chemical models of dense core precursors. Astron Astrophys 515:A66. doi: 10.1051/0004-6361/200913896 CrossRefGoogle Scholar
  18. 18.
    Hersant F, Wakelam V, Dutrey A, Guilloteau S, Herbst E (2009) Cold CO in circumstellar disks. On the effects of photodesorption and vertical mixing. Astron Astrophys 493:L49–L52. doi: 10.1051/0004-6361:200811082 CrossRefGoogle Scholar
  19. 19.
    Crimier N, Ceccarelli C, Maret S, Bottinelli S, Caux E, Kahane C, Lis DC, Olofsson J (2010) The solar type protostar IRAS16293-2422: new constraints on the physical structure. Astron Astrophys 519:A65. doi: 10.1051/0004-6361/200913112 CrossRefGoogle Scholar
  20. 20.
    Serena V, Collings MP, Dever JW, McCoustra MRS, Williams DA (2004) Evaporation of ices near massive stars: models based on laboratory temperature programmed desorption data. Mon Not Roy Astron Soc 354:1141–1145. doi: 10.1111/j.1365-2966.2004.08273.x CrossRefGoogle Scholar
  21. 21.
    Aikawa Y, Wakelam V, Garrod RT, Herbst E (2008) Molecular evolution and star formation: from prestellar cores to protostellar cores. Astrophys J 674:984–996. doi: 10.1086/524096 CrossRefGoogle Scholar
  22. 22.
    Wakelam V, Herbst E, Loison JC, Smith IWM, Chandrasekaran V, Pavone B et al (2012) A kinetic database for astrochemistry (KIDA). Astrophys J Supplt Volume 199, Issue 1, article id. 21Google Scholar
  23. 23.
    Semenov D, Wiebe D, Henning Th (2006) Gas-phase CO in protoplanetary disks: a challenge for turbulent mixing. Astrophys J 647:L57–L60. doi: 10.1086/507096 CrossRefGoogle Scholar
  24. 24.
    Herbst E, van Dishoeck EF (2009) Complex organic interstellar molecules. Ann Rev Astron Astr 47:427–480. doi: 10.1146/annurev-astro-082708-101654 CrossRefGoogle Scholar
  25. 25.
    Garrod RT, Weaver SLW, Herbst E (2008) Complex chemistry in star-forming regions: an expanded gas-grain warm-up chemical model. Astrophys J 682:283–302. doi: 10.1086/588035 CrossRefGoogle Scholar
  26. 26.
    Aikawa Y, Furuya K, Wakelam V et al (2011) Hydrodynamical-chemical models from prestellar cores to protostellar cores. In: The molecular Universe, Proceedings of the international astronomical union, IAU symposium Conference held in Toledo (Spain), June 2011Google Scholar
  27. 27.
    Prasad SS, Tarafdar SP (1983) UV radiation field inside dense clouds – Its possible existence and chemical implications. Astrophys J 267:603–609. doi: 10.1086/160896 CrossRefGoogle Scholar
  28. 28.
    Prasad SS, Huntress WT (1980) A model for gas phase chemistry in interstellar clouds. II – Nonequilibrium effects and effects of temperature and activation energies. Astrophys J 239:151–165. doi: 10.1086/158097 CrossRefGoogle Scholar
  29. 29.
    Gredel R, Lepp S, Dalgarno A, Herbst E (1989) Cosmic-ray-induced photodissociation and photoionization rates of interstellar molecules. Astrophys J 347:289–293. doi: 10.1086/168117 CrossRefGoogle Scholar
  30. 30.
    Rimmer PB, Herbst E, Morata O, Roueff E (2012) Observing a column-dependent ζ in dense interstellar sources: the case of the horsehead nebula. Astron Astrophys 537:A7. doi: 10.1051/0004-6361/201117048 CrossRefGoogle Scholar
  31. 31.
    Wagenblast R, Hartquist TW (1990) Ultraviolet pumping of molecular hydrogen in diffuse cloud shocks. Mon Not Roy Astron Soc 244:265–268Google Scholar
  32. 32.
    Loison JC, Halvick Ph, Bergeat A, Hickson KM, Wakelam V (2012) Review of OCS gas-phase reactions in dark cloud chemical models. Mon Not Roy Astron Soc Volume 421, Issue 2, pp. 1476–1484Google Scholar
  33. 33.
    Wakelam V, Herbst E, Selsis F (2006) The effect of uncertainties on chemical models of dark clouds. Astron Astrophys 451:551–562. doi: 10.1051/0004-6361:20054682 CrossRefGoogle Scholar
  34. 34.
    Wakelam V, Smith IWM, Herbst E, Troe J, Geppert W, Linnartz H et al (2010) Reaction networks for interstellar chemical modelling: improvements and challenges. Space Sci Rev 156:13–72CrossRefGoogle Scholar
  35. 35.
    Ruffle DP, Rae JGL, Pilling MJ, Hartquist TW, Herbst E (2002) A network for interstellar CO – The first application of objective reduction techniques in astrochemistry. Astron Astrophys 381:L13–L16. doi: 10.1051/0004-6361:20011544 CrossRefGoogle Scholar
  36. 36.
    Rae JGL, Bell N, Hartquist TW, Pilling MJ, Ruffle DP (2002) Reduced networks governing the fractional ionisation in interstellar molecular clouds. Astron Astrophys 383:738–746. doi: 10.1051/0004-6361:20011748 CrossRefGoogle Scholar
  37. 37.
    Semenov D, Wiebe D, Henning Th (2004) Reduction of chemical networks. II. Analysis of the fractional ionisation in protoplanetary discs. Astron Astrophys 417:93–106. doi: 10.1051/0004-6361:20034128 CrossRefGoogle Scholar
  38. 38.
    Wiebe D, Semenov D, Henning Th (2003) Reduction of chemical networks. I. The case of molecular clouds. Astron Astrophys 399:197–210. doi: 10.1051/0004-6361:20021773 CrossRefGoogle Scholar
  39. 39.
    Hasegawa TI, Herbst E, Leung CM (1992) Models of gas-grain chemistry in dense interstellar clouds with complex organic molecules. Astrophys J Suppl 82:167–195CrossRefGoogle Scholar
  40. 40.
    Westley MS, Baragiola RA, Johnson RE, Baratta GA (1995) Ultraviolet photodesorption from water ice. Planet Space Sci 43:1311–1315CrossRefGoogle Scholar
  41. 41.
    Öberg KI, Linnartz H, Visser R, van Dishoeck EF (2009) Photodesorption of ices. II. H2O and D2O. Astrophys J 693:1209–1218CrossRefGoogle Scholar
  42. 42.
    Hasegawa TI, Herbst E (1993) New gas-grain chemical models of quiescent dense interstellar clouds – the effects of H2 tunnelling reactions and cosmic ray induced desorption. Mon Not Roy Astron Soc 261:83–102Google Scholar
  43. 43.
    Herbst E, Cuppen HM (2006) Interstellar chemistry special feature: monte carlo studies of surface chemistry and nonthermal desorption involving interstellar grains. Proc Natl Acad Sci USA 103:12257–12262CrossRefGoogle Scholar
  44. 44.
    Garrod RT, Wakelam V, Herbst E (2007) Non-thermal desorption from interstellar dust grains via exothermic surface reactions. Astron Astrophys 467:1103–1115CrossRefGoogle Scholar
  45. 45.
    Charnley SB, Tielens AGGM, Rodgers SD (1997) Deuterated methanol in the orion compact ridge. Astrophys J Lett 482:L203CrossRefGoogle Scholar
  46. 46.
    Lohmar I, Krug J (2006) The sweeping rate in diffusion-mediated reactions on dust grain surfaces. Mon Not Roy Astron Soc 370:1025–1033Google Scholar
  47. 47.
    Biham O, Furman I, Pirronello V, Vidali G (2001) Master equation for hydrogen recombination on grain surfaces. Astrophys J 553:595–603CrossRefGoogle Scholar
  48. 48.
    Green NJB, Toniazzo T, Pilling MJ, Ruffle DP, Bell N, Hartquist TW (2001) A stochastic approach to grain surface chemical kinetics. Astron Astrophys 375:1111–1119CrossRefGoogle Scholar
  49. 49.
    Stantcheva T, Shematovich VI, Herbst E (2002) On the master equation approach to diffusive grain-surface chemistry: the H, O, CO system. Astron Astrophys 391:1069–1080CrossRefGoogle Scholar
  50. 50.
    Charnley SB (1998) Stochastic astrochemical kinetics. Astrophys J Lett 509:L121–L124CrossRefGoogle Scholar
  51. 51.
    Charnley SB (2001) Stochastic theory of molecule formation on dust. Astrophys J 562:L99–L102. doi: 10.1086/324753 CrossRefGoogle Scholar
  52. 52.
    Vasyunin AI, Semenov DA, Wiebe DS, Henning Th (2009) A unified monte carlo treatment of gas-grain chemistry for large reaction networks. I. Testing validity of rate equations in molecular clouds. Astrophys J 691:1459–1469CrossRefGoogle Scholar
  53. 53.
    Lipshtat A, Biham O (2004) Efficient simulations of gas-grain chemistry in interstellar clouds. Phys Rev Lett 93(17):170601CrossRefGoogle Scholar
  54. 54.
    Barzel B, Biham O (2007) Efficient simulations of interstellar gas-grain chemistry using moment equations. Astrophys J Lett 658:L37–L40CrossRefGoogle Scholar
  55. 55.
    Du F, Parise B (2011) A hybrid moment equation approach to gas-grain chemical modeling. Astron Astrophys 530:A131. doi: 10.1051/0004-6361/201016262 CrossRefGoogle Scholar
  56. 56.
    Caselli P, Hasegawa TI, Herbst E (1998) A Proposed modification of the rate equations for reactions on grain surfaces. Astrophys J 495:309–316. doi: 10.1086/305253 CrossRefGoogle Scholar
  57. 57.
    Garrod RT (2008) A new modified-rate approach for gas-grain chemical simulations. Astron Astrophys 491:239–251. doi: 10.1051/0004-6361:200810518 CrossRefGoogle Scholar
  58. 58.
    Garrod RT, Vasyunin AI, Semenov DA, Wiebe DS, Henning Th (2009) A new modified-rate approach for gas-grain chemistry: comparison with a unified large-scale monte carlo simulation. Astrophys J Lett 700:L43–L46CrossRefGoogle Scholar
  59. 59.
    Cuppen HM, van Dishoeck EF, Herbst E, Tielens AGGM (2009) Microscopic simulation of methanol and formaldehyde ice formation in cold dense cores. Astron Astrophys 508:275–287CrossRefGoogle Scholar
  60. 60.
    Hasegawa TI, Herbst E (1993) Three-phase chemical models of dense interstellar clouds – gas dust particle mantles and dust particle surfaces. Mon Not Roy Astron Soc 263:589–606Google Scholar
  61. 61.
    Fayolle EC, Öberg KI, Cuppen HM, Visser R, Linnartz H (2011) Laboratory H2O:CO2 ice desorption data: entrapment dependencies and its parameterization with an extended three-phase model. Astron Astrophys 529:A74CrossRefGoogle Scholar
  62. 62.
    Vasyunin AI, Herbst E (2011) New chemical models for new era observations: a multiphase Monte Carlo model of gas-grain chemistry. In IAU symposium, vol 280 of IAU symposium Conference held in Toledo (Spain), June 2011Google Scholar
  63. 63.
    Öberg KI, van Broekhuizen F, Fraser HJ, Bisschop SE, van Dishoeck EF, Schlemmer S (2005) Competition between CO and N2 desorption from interstellar ices. Astrophys J Lett 621:L33–L36CrossRefGoogle Scholar
  64. 64.
    Acharyya K, Fuchs GW, Fraser HJ, van Dishoeck EF, Linnartz H (2007) Desorption of CO and O2 interstellar ice analogs. Astron Astrophys 466:1005–1012CrossRefGoogle Scholar
  65. 65.
    Bolina AS, Wolff AJ, Brown WA (2005) Reflection absorption infrared spectroscopy and temperature-programmed desorption studies of the adsorption and desorption of amorphous and crystalline water on a graphite surface. J Phys Chem B 109:16836–16845CrossRefGoogle Scholar
  66. 66.
    Fraser HJ, Collings MP, McCoustra MRS, Williams DA (2001) Thermal desorption of water ice in the interstellar medium. Mon Not Roy Astron Soc 327:1165–1172CrossRefGoogle Scholar
  67. 67.
    Green SD, Bolina AS, Chen R, Collings MP, Brown WA, McCoustra MRS (2009) Applying laboratory thermal desorption data in an interstellar context: sublimation of methanol thin films. Mon Not Roy Astron Soc 398:357–367CrossRefGoogle Scholar
  68. 68.
    Collings MP, Anderson MA, Chen R, Dever JW, Viti S, Williams DA, McCoustra MRS (2004) A laboratory survey of the thermal desorption of astrophysically relevant molecules. Mon Not Roy Astron Soc 354:1133–1140. doi: 10.1111/j.1365-2966.2004.08272.x CrossRefGoogle Scholar
  69. 69.
    Öberg KI, Fayolle EC, Cuppen HM, van Dishoeck EF, Linnartz H (2009) Quantification of segregation dynamics in ice mixtures. Astron Astrophys 505:183–194CrossRefGoogle Scholar
  70. 70.
    Matar E, Congiu E, Dulieu F, Momeni A, Lemaire JL (2008) Mobility of D atoms on porous amorphous water ice surfaces under interstellar conditions. Astron Astrophys 492:L17–L20CrossRefGoogle Scholar
  71. 71.
    Watanabe N, Nagaoka A, Hidaka H, Shiraki T, Chigai T, Kouchi A (2006) Dependence of the effective rate constants for the hydrogenation of CO on the temperature and composition of the surface. Planet Space Sci 54:1107–1114CrossRefGoogle Scholar
  72. 72.
    Fuchs GW, Cuppen HM, Ioppolo S, Romanzin C, Bisschop SE, Andersson S, van Dishoeck EF, Linnartz H (2009) Hydrogenation reactions in interstellar CO ice analogues. A combined experimental/theoretical approach. Astron Astrophys 505:629–639CrossRefGoogle Scholar
  73. 73.
    Miyauchi N, Hidaka H, Chigai T, Nagaoka A, Watanabe N, Kouchi A (2008) Formation of hydrogen peroxide and water from the reaction of cold hydrogen atoms with solid oxygen at 10 K. Chem Phys Lett 456:27–30CrossRefGoogle Scholar
  74. 74.
    Ioppolo S, Cuppen HM, Romanzin C, van Dishoeck EF, Linnartz H (2008) Laboratory evidence for efficient water formation in interstellar ices. Astrophys J 686:1474–1479CrossRefGoogle Scholar
  75. 75.
    Oba Y, Watanabe N, Kouchi A, Hama T, Pirronello V (2010) Experimental study of CO2 formation by surface reactions of non-energetic OH radicals with CO molecules. Astrophys J Lett 712:L174–L178CrossRefGoogle Scholar
  76. 76.
    Ioppolo S, Cuppen HM, van Dishoeck EF, Linnartz H (2011) Surface formation of HCOOH at low temperature. Mon Not Roy Astron Soc 410:1089–1095CrossRefGoogle Scholar
  77. 77.
    Ioppolo S, van Boheemen Y, Cuppen HM, van Dishoeck EF, Linnartz H (2011) Surface formation of CO2 ice at low temperatures. Mon Not Roy Astron Soc 413:2281–2287CrossRefGoogle Scholar
  78. 78.
    Bisschop SE, Fuchs GW, van Dishoeck EF, Linnartz H (2007) H-atom bombardment of CO2, HCOOH, and CH3CHO containing ices. Astron Astrophys 474:1061–1071CrossRefGoogle Scholar
  79. 79.
    Öberg KI, Garrod RT, van Dishoeck EF, Linnartz H (2009) Formation rates of complex organics in UV irradiated CH3OH-rich ices. I. experiments. Astron Astrophys 504:891–913CrossRefGoogle Scholar
  80. 80.
    Herbst E, Klemperer W (1973) The formation and depletion of molecules in dense interstellar clouds. Astrophys J 185:505–534. doi: 10.1086/152436 CrossRefGoogle Scholar
  81. 81.
    Carty D, Goddard A, Kahler SPK, Sims IR, Smith IWM (2006) Kinetics of the radical-radical reaction, O(3PJ) + OH(X2P) → O2 + H, at temperatures down to 39 K. J Phys Chem A 110:3101–3110CrossRefGoogle Scholar
  82. 82.
    Watson WD (1973) The rate of formation of interstellar molecules by ion-molecule reactions. Astrophys J 183:L17–L20. doi: 10.1086/181242 CrossRefGoogle Scholar
  83. 83.
    Pagani L, Olofsson AOH, Bergman P et al (2003) Low upper limits on the O2 abundance from the odin satellite. Astron Astrophys 402:L77–L81. doi: 10.1051/0004-6361:20030344 CrossRefGoogle Scholar
  84. 84.
    Goldsmith PF, Melnick GJ, Bergin EA et al (2000) O2 in interstellar molecular clouds. Astrophys J 539:L123–L127. doi: 10.1086/312854 CrossRefGoogle Scholar
  85. 85.
    Larsson B, Liseau R, Pagani L et al (2007) Molecular oxygen in the ρ Ophiuchi cloud. Astron Astrophys 466:999–1003. doi: 10.1051/0004-6361:20065500 CrossRefGoogle Scholar
  86. 86.
    Liseau R, Larsson B, Bergman P, Pagani L, Black JH, Hjalmarson Å, Justtanont K (2010) O18O and C18O observations of ρ Ophiuchi A. Astron Astrophys 510:A98. doi: 10.1051/0004-6361/200913567 CrossRefGoogle Scholar
  87. 87.
    Goldsmith PF, Liseau R, Bell TA et al (2011) Herschel measurements of molecular oxygen in orion. Astrophys J 737:96. doi: 10.1088/0004-637X/737/2/96 CrossRefGoogle Scholar
  88. 88.
    Quan D, Herbst E, Millar TJ, Hassel GE, Lin SY, Guo H, Honvault P, Xie D (2008) New theoretical results concerning the interstellar abundance of molecular oxygen. Astrophys J 681:1318–1326. doi: 10.1086/588007 CrossRefGoogle Scholar
  89. 89.
    Bergin EA, Melnick GJ, Stauffer JR (2000) Implications of submillimeter wave astronomy satellite observations for interstellar chemistry and star formation. Astrophys J 539:L129–L132. doi: 10.1086/312843 CrossRefGoogle Scholar
  90. 90.
    Tielens AGGM, Hagen W (1982) Model calculations of the molecular composition of interstellar grain mantles. Astron Astrophys 114:245–260Google Scholar
  91. 91.
    Hollenbach D, Kaufman MJ, Bergin EA, Melnick GJ (2009) Water, O2, and Ice in molecular clouds. Astrophys J 690:1497–1521. doi: 10.1088/0004-637X/690/2/1497 CrossRefGoogle Scholar
  92. 92.
    Whittet DCB (2010) Oxygen depletion in the interstellar medium: implications for grain models and the distribution of elemental oxygen. Astrophys J 710:1009–1016. doi: 10.1088/0004-637X/710/2/1009 CrossRefGoogle Scholar
  93. 93.
    Hincelin U, Wakelam V, Hersant F, Guilloteau S, Loison JC, Honvault P, Troe J (2011) Oxygen depletion in dense molecular clouds: a clue to a low O2 abundance? Astron Astrophys 530:A61. doi: 10.1051/0004-6361/201016328 CrossRefGoogle Scholar
  94. 94.
    Ilgner M, Nelson RP (2006) On the ionisation fraction in protoplanetary disks. I. Comparing different reaction networks. Astron Astrophys 445:205–222. doi: 10.1051/0004-6361:20053678 CrossRefGoogle Scholar
  95. 95.
    Ceccarelli C, Hollenbach DJ, Tielens AGGM (1996) Far-infrared line emission from collapsing protostellar envelopes. Astrophys J 471:400–426. doi: 10.1086/177978 CrossRefGoogle Scholar
  96. 96.
    Sims IR, Queffelec JL, Defrance A, Rebrion-Rowe C, Travers D, Bocherel P, Rowe BR, Smith IWM (1994) Ultralow temperature kinetics of neutral-neutral reactions. The technique and results for the reactions CN + O2 down to 13 K and CN + NH3 down to 25 K. J Chem Phys 100:4229–4241. doi: 10.1063/1.467227 CrossRefGoogle Scholar
  97. 97.
    Feng W, Hershberger JF (2009) Reinvestigation of the branching ratio of the CN + O2 reaction. J Phys Chem 113:3523–3527CrossRefGoogle Scholar
  98. 98.
    Harada N, Herbst E (2008) Modeling carbon chain anions in L1527. Astrophys J 685:272–280. doi: 10.1086/590468 CrossRefGoogle Scholar
  99. 99.
    Daranlot J, Hincelin U, Bergeat A, Costes M, Loison JC, Wakelam V, Hickson KM (2012) Elemental nitrogen partitioning in dense interstellar clouds. In: Proceedings of the National Academy of Science submitted, June 26, 2012 vol. 109 no. 26 10233-10238. doi:  10.1073/pnas.1200017109
  100. 100.
    Herbst E (2008) Chemistry in the ISM: the ALMA (r)evolution. The cloudy crystal ball of one astrochemist. Astrophys Space Sci 313:129–134. doi: 10.1007/s10509-007-9639-9 CrossRefGoogle Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 2013

Authors and Affiliations

  • Valentine Wakelam
    • 1
    • 2
  • Herma M. Cuppen
    • 3
  • Eric Herbst
    • 4
  1. 1.LABUniv. BordeauxFloiracFrance
  2. 2.LABCNRSFloiracFrance
  3. 3.Theoretical Chemistry, Institute for Molecules and MaterialsRadboud University NijmegenNijmegenThe Netherlands
  4. 4.Departments of Chemistry, Astronomy, and PhysicsUniversity of VirginiaCharlottesvilleUSA

Personalised recommendations