On the deuteration of CH in dense interstellar clouds via the reaction CH + HD CHD+ + H
LETMEX, Université de Nice Sophia Antipolis, Parc Valrose, UFR Sciences, 06108 Nice Cedex 2, France
2 Departments of Physics and Astronomy, The Ohio State University, Columbus, OH 43210, USA
Corresponding author: E. Herbst, firstname.lastname@example.org
Accepted: 6 July 2001
Although deuterium isotope fractionation in cold, dark interstellar clouds is reasonably well understood via gas-phase chemistry, there are some discrepancies between observation and theory. For example, the observed abundance ratio between the deuterated species C3HD and the cyclic molecule C3H2 is significantly higher than most theoretical values unless the exchange reaction C3H + HD C3H2D+ + H2 is efficient. In this paper, we report quantum chemical and dynamical calculations on this reaction, which show it to possess a large activation energy barrier and to be very slow at all normal interstellar temperatures.
Key words: ISM: abundances / ISM: molecules / molecular processes
© ESO, 2001