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Modelling of deuterium chemistry and its application to molecular clouds
H. Roberts and
Received 22 May 2000 / Accepted 4 July 2000
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 deuteration, extended previous models to include S-D bonds for the first time and included the gas-phase chemistry of some doubly-deuterated species. We present models for a wide range of physical parameters, including density, temperature, elemental abundances, and the freeze out of molecules on to dust grains. We discuss the detailed fractionation of particular species and show how fractionation can be used to probe the history of interstellar matter. The freeze out of molecules onto dust leads to significant enhancement in fractionation ratios and, in particular, to large fractionation in doubly-deuterated species.
Key words: ISM: abundances ISM: molecules galaxies: abundances galaxies: ISM galaxies: Magellanic Clouds
Send offprint requests to: H. Roberts (email@example.com)
Online publication: September 5, 2000