Deuterium Fractionation in Interstellar Clouds

@article{Millar2003DeuteriumFI,
  title={Deuterium Fractionation in Interstellar Clouds},
  author={Tom J. Millar},
  journal={Space Science Reviews},
  year={2003},
  volume={106},
  pages={73-86}
}
  • T. Millar
  • Published 1 April 2003
  • Physics
  • Space Science Reviews
This paper reviews the chemical processes responsible for fractionating deuterium in interstellar molecules. I show that this process is intrinsically a low temperature phenomenon and discuss how the degree of enhancement of the deuterium content of molecules is related to the physical conditions, particularly abundances, in molecular clouds. If significant amounts of abundant species, such as CO, are frozen out on to interstellar dust grains, the resulting enhancement in H2D+ can result in its… 
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References

SHOWING 1-10 OF 33 REFERENCES
Modelling of deuterium chemistry and its application to molecular clouds
We have developed new models of the chemistry of deuterium for investigating fractionation in interstellar molecular clouds. We have incorporated the latest information on reactions which affect
The importance of new rate coefficients for deuterium fractionation reactions in interstellar chemistry
Rate coefficients for deuterium fractionation reactions that are important at low temperatures have recently been studied at 10 K in the laboratory for the first time. In this paper, we incorporate
A model of the chemistry in cometary comae: deuterated molecules
ABSTRA C T We have developed a combined chemical and hydrodynamical model of cometary comae. The model is described and used to follow the deuterium chemistry occurring in the coma after the
Gas-Phase Production of NHD2 in L134N
We show analytically that large abundances of NH2D and NHD2 can be produced by gas-phase chemistry in the interiors of cold dense clouds. The calculated fractionation ratios are in good agreement
Gas-Phase Formation of Doubly-Deuterated Species
We present the first results from a time-dependent chemical model to include a gas-phase reaction scheme for producing doubly-deuterated species. Under normal conditions the formation of these
Deuterium fractionation in dense ammonia cores
We report observations of several deuterated species in the dark clouds L134N and TMC1, and in particular of NH2D (deuterated ammonia). NH2D has been detected for the first time towards the dense
Sublimation from icy jets as a probe of the interstellar volatile content of comets
TLDR
High-resolution observations of emission from the molecules HNC, DCN and HDO associated with comet Hale–Bopp reveal arc-like structures—icy jets—offset from (but close to) the nucleus, and suggest that, by mass, Hale-Bopp (and by inference the outer regions of the early solar nebula) consists of largely unprocessed interstellar material.
DETECTION OF TRIPLY DEUTERATED AMMONIA IN THE BARNARD 1 CLOUD
We report the detection of the ground-state rotational transition JK = 10 → 00 (0a → 0s) of triply deuterated ammonia at 309.91 GHz in the Barnard 1 cloud, obtained with the Caltech Submillimeter
The D/H Ratio in Methane in Titan: Origin and History
Abstract We propose a new interpretation of the D/H ratio in CH4 observed in the atmosphere of Titan. Using a turbulent evolutionary model of the subnebula of Saturn (O. Mousis et al. 2002,
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