Deuterated interstellar and circumstellar molecules: D/H ratio and dominant formation processes


There are several constraints associated with the different models used in accounting for the D/H ratio observed of singly and multiply deuterated interstellar and circumstellar molecular species. Thermodynamically, the most distinctive difference between a molecule and its deuterated analogue is the zero point energy (ZPE). Applying high level quantum chemical calculations, the ZPE for all H-containing and their corresponding D-analogues for all interstellar/circumstellar molecular species considered in this study are determined. From the difference in the ZPE between the H-containing and the corresponding D-analogue, Boltzmann factor is computed for all the systems using the excitation temperature/molecular cloud temperature for the known D-molecules and a range of temperature for others. From the results, there is a direct correlation between the Boltzmann factors and the D/H ratios. Pronounced deuterium fractionation occurs at larger values of Boltzmann factor resulting in the observed high D/H ratios. Increased deuterium fractionation at low temperature suggests that grain surface reactions are the major formation processes for deuterated molecules. This implies that at lower temperature (higher Boltzmann factor), the exchange reaction involving deuterium or deuterium fractionation is much pronounced resulting in the distribution and redistribution of deuterium among various species. The implications of these results and the possibility of detecting more D-molecules are discussed.

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  1. 1.

    A C Cheung, D M Rank, C H Townes, D D Thornton and W J Welch Phys Rev Lett25 1701 (1968)

    ADS  Article  Google Scholar 

  2. 2.

    A C Cheung, D M Rank, C H Townes, D D Thornton and W J Welch Nature221 626–628 (1969)

    ADS  Article  Google Scholar 

  3. 3.

    L E Synder, D Buhl, B Zuckerman and P Palmer Phys Rev Lett22 679 (1969)

    ADS  Article  Google Scholar 

  4. 4.

    R W Wilson, K B Jefferts and A A Penzias ApJ161 L43 (1970)

    ADS  Article  Google Scholar 

  5. 5.

    J A Ball, C A Gottlieb, A E Lilley and H E Radford ApJ162 L203 (1970)

    ADS  Article  Google Scholar 

  6. 6.

    C P Endres, S Schlemmer, P Schilke, J Stutzki and H S P Müller J. Mol. Spectrosc327 95 (2016)

    ADS  Article  Google Scholar 

  7. 7. Accessed in September 2018.

  8. 8.

    E E Etim and E Arunan Planex Newletter5 16 (2015)

    Google Scholar 

  9. 9.

    (a) A J Markwick, S B Charnley, H M Butner and T J Millar ApJ627 L117 (2005). (b) G Wlodarczak Journal of Molecular Structure347 131 (1995)

  10. 10.

    B E Turner and B Zuckerman ApJ225 L75 (1978)

    ADS  Article  Google Scholar 

  11. 11.

    B E Turner ApJ362 L29 (1990)

    ADS  Article  Google Scholar 

  12. 12.

    S Lacour, M K Andre and P Sonnentrucker A&A430 967 (2005)

    ADS  Article  Google Scholar 

  13. 13.

    M Gerin, F Combes and G Wlodarczak ApJ259 L35 (1992a)

    Google Scholar 

  14. 14.

    J Cernicharo, B Tercero and A Fuente ApJ771 L10 (2013)

    ADS  Article  Google Scholar 

  15. 15.

    D C Lis, E Roueff and M Gerin ApJ571 L55 (2002)

    ADS  Article  Google Scholar 

  16. 16.

    K B Jefferts, A A Penzias and R W Wilson, ApJ179 L57 (1973)

    ADS  Article  Google Scholar 

  17. 17.

    J E Lee and E A Bergin ApJ799 104 (2015)

    ADS  Article  Google Scholar 

  18. 18.

    H Roberts, G A Fuller, T J Millar, J Hatchell and J V Buckle A&A381 1026 (2002)

    ADS  Article  Google Scholar 

  19. 19.

    H Roberts and T J Millar A&A471 849 (2007)

    ADS  Article  Google Scholar 

  20. 20.

    T J Millar Astronomy and Geophysics 46, 2, 2.29 2.32 (2005)

  21. 21.

    C Ceccarelli Planetary and Space Science50 1267 (2002)

    ADS  Article  Google Scholar 

  22. 22.

    L Spitzer, J F Drake and E B Jenkins ApJ181 L116 (1973)

    ADS  Article  Google Scholar 

  23. 23.

    V Taquet, C Ceccarelli and C Kahane ApJL748 L3

  24. 24.

    M Emprechtinger, P Caselli, N H Volgenau, J Stutzki and M C Wiedner A&A493 89 (2009)

    ADS  Article  Google Scholar 

  25. 25.

    L Dore, P Caselli, S Beninatil, T Bourke, P C Myers and G Cazzoli1 A&A413 1177 (2004)

  26. 26.

    B Parise, C Ceccarelli, A G G M Tielens, A Castets, E Caux, B Lefloch and S Maret A&A453 949 (2006)

    ADS  Article  Google Scholar 

  27. 27.

    D Rehder, Chemistry in Space. Wiley, Weinheim, Germany (2010)

    Google Scholar 

  28. 28.

    T J Millar, H Roberts, A J Markwick and S B Charnley Philos. Trans. R. Soc. Lond.358 2535 (2000)

    ADS  Article  Google Scholar 

  29. 29.

    A G G M Tielens A&A119 177 (1983)

    ADS  Google Scholar 

  30. 30.

    S Kong, P Caselli, J C Tan, V Wakelam and O. Sipila, Submitted, arXiv:1312.0971[astro-ph.SR] (2015)

  31. 31.

    P M Solomon and N J Woolf ApJ180 L89 (1973)

    ADS  Article  Google Scholar 

  32. 32.

    M J Frisch, G W Trucks and H B Schlegel G09:RevC.01, Gaussian, Inc., Wallingford CT (2009)

  33. 33.

    L A Curtiss, P C Redfern and K Raghavachari JChPh126 084108 (2007a)

    ADS  Google Scholar 

  34. 34.

    L A Curtiss, P C Redfern and K Raghavachari, JChPh127 124105 (2007b)

    ADS  Google Scholar 

  35. 35.

    E E Etim and E Arunan European Physical Journal Plus131 448 (2016)

    ADS  Article  Google Scholar 

  36. 36.

    E E Etim and E Arunan, Advances in Space Research59 1161 (2017)

    ADS  Article  Google Scholar 

  37. 37.

    E E Etim, P Gorai, A Das, S K Chakrabati and E Arunan The Astrophysical Journal832 144 (2016)

    ADS  Article  Google Scholar 

  38. 38.

    E E Etim, E J Inyang, O A Ushie, I E Mbakara, C Andrew and U Lawal FUW Trends in Science and Technology Journal2 665 (2017)

    Google Scholar 

  39. 39.

    E E Etim, G Gorai, A Das and E Arunan Astrophysics and Space Science363 6 (2018a)

    ADS  Article  Google Scholar 

  40. 40.

    E E Etim, P Gorai, A Das, S K Chakrabarti and E Arunan, Advances in Space Research61 2870–2880 (2018b)

    ADS  Article  Google Scholar 

  41. 41.

    J M L Martin and G de Oliveira J Chem Phys111 1843 (1999)

    Google Scholar 

  42. 42.

    A Coutens, C Vastel, and E Caux A&A539 132 (2012)

    Article  Google Scholar 

  43. 43.

    H M Butner, S B Charnley and C Ceccarelli ApJ659 L137 (2007)

    ADS  Article  Google Scholar 

  44. 44.

    C Vastel, T G Phillips, C Ceccarelli and J Pearson ApJ593 L97 (2003)

    ADS  Article  Google Scholar 

  45. 45.

    R Stark, F van der Tak and E F van Dishoeck ApJ521 L67 (1999)

    ADS  Article  Google Scholar 

  46. 46.

    E van Dishoeck, G A Blake, D J Jansen and T D Groesbeck ApJ 447 760 (1995)

    ADS  Article  Google Scholar 

  47. 47.

    N Marcelino, J Cernicharo, E Roueff, M Gerin and R Mauersberger ApJ620 308 (2005)

    ADS  Article  Google Scholar 

  48. 48.

    J Hatchell A&A403 L25 (2003)

    ADS  Article  Google Scholar 

  49. 49.

    L Loinard, A Castets, C Ceccarelli, E Caux and A G G M Tielens ApJ552 L163 (2001)

    ADS  Article  Google Scholar 

  50. 50.

    N Sakai, T Sakai, T Hirota and S Yamamoto ApJ702 1025 (2009)

  51. 51.

    D A Howe, T J Millar, P Schike and C M Walmsley Mont. Not. R. Astron. Soc. 267 59 (1994)

    ADS  Article  Google Scholar 

  52. 52.

    J M Macleod, L W Avery and N W Broten ApJ251 L33 (1981)

    ADS  Article  Google Scholar 

  53. 53.

    B E Turner ApJ347 L39 (1989)

    ADS  Article  Google Scholar 

  54. 54.

    B Praise, A Castets and E Herbst A&A416 159 (2004)

    ADS  Article  Google Scholar 

  55. 55.

    L H Coudert, B J Drouin and B Tercero ApJ779 119 (2013)

    Article  Google Scholar 

  56. 56.

    M Gerin, F Combes, G Wlodarczak, P Encrenaz and C Laurent ApJ 253 L29 (1992b)

    ADS  Google Scholar 

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EEE acknowledges a research fellowship from the Indian Institute of Science, Bangalore.

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Etim, E.E., Akpan, N.I., Adelagun, R.A.O. et al. Deuterated interstellar and circumstellar molecules: D/H ratio and dominant formation processes. Indian J Phys (2020).

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  • Abundance
  • Molecules
  • Astrochemistry
  • Interstellar medium
  • Deuterium


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