EDP Sciences
Free access
Volume 386, Number 3, May II 2002
Page(s) 1139 - 1142
Section Atomic and molecular data
DOI http://dx.doi.org/10.1051/0004-6361:20020312

A&A 386, 1139-1142 (2002)
DOI: 10.1051/0004-6361:20020312

The gas-phase destruction of interstellar carbon dioxide: Calculations on the reactions between CO $\mathsf{_{2}}$ and H $\mathsf{_{2}}$ and between CO $\mathsf{_{2}}$ and H

D. Talbi1 and E. Herbst2

1  LETMEX, Université de Nice Sophia Antipolis, Parc Valrose, U.F.R. Sciences, 06108 Nice Cedex 2, France
2  Departments of Physics and Astronomy, The Ohio State University, Columbus, OH 43210, USA

(Received 27 December 2001 / Accepted 28 February 2002 )

Carbon dioxide is an abundant component of cold interstellar grains, but its gas-phase abundance is not high. To partially explain this low abundance, it has been suggested that gas-phase CO 2 is destroyed by reaction with both atomic and molecular hydrogen. Although there are experimental studies concerning the rate of the reaction between CO 2 and H, there are no modern experimental studies for the analogous reaction with H 2. In this paper, we report quantum chemical and dynamical research on the reactive systems CO 2 + H and CO 2 + H 2. Our results for the former are in excellent agreement with experiment and previous theory, while our results for the latter show this reaction to possess an extremely large potential energy barrier, far in excess of the reaction endothermicity.

Key words: ISM: abundances -- ISM: molecules -- molecular processes

Offprint request: E. Herbst, herbst@mps.ohio-state.edu

© ESO 2002