Multiple Paths of Deuterium Fractionation in Protoplanetary Disks

@article{Aikawa2018MultiplePO,
  title={Multiple Paths of Deuterium Fractionation in Protoplanetary Disks},
  author={Yuri Aikawa and Kenji Furuya and Ugo Hincelin and Eric Herbst},
  journal={Japan Geoscience Union},
  year={2018}
}
We investigate deuterium chemistry coupled with the nuclear spin-state chemistry of H$_2$ and H$_3^+$ in protoplanetary disks. Multiple paths of deuterium fractionation are found; exchange reactions with D atoms, such as HCO$^+$ + D, are effective in addition to those with HD. In a disk model with grain sizes appropriate for dark clouds, the freeze-out of molecules is severe in the outer midplane, while the disk surface is shielded from UV radiation. Gaseous molecules, including DCO$^+$, thus… 
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