Collisions between H-3(+) and HD in molecular clouds lead to the fractionation of deuterium in H2D+ at temperatures below 20 K. In this article, we describe the chemistry of H2D+ and discuss how variations in temperature and elemental abundances affect the level of fractionation in H2D+ and other species. We describe how accretion of gas-phase molecules on to cold dust grains enhances the deuteration in several molecules including doubly deuterated molecules. Mie show that the ion-neutral drift velocities attained in slow Alfven waves can destroy H2D+ in non-thermal reactions. As a result, the degree of fractionation can be reduced and we discuss observational consequences of such a model for the dark dust cloud TMC-1.
|Number of pages||13|
|Journal||PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY OF LONDON SERIES A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES|
|Publication status||Published - Feb 2000|
ASJC Scopus subject areas
Millar, TJ., Roberts, H., Markwick, A. J., & Charnley, S. B. (2000). The role of H2D+ in the deuteration of interstellar molecules. PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY OF LONDON SERIES A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES, 358(1774), 2535-2547.