THE C({sup 3}P) + NH{sub 3} REACTION IN INTERSTELLAR CHEMISTRY. II. LOW TEMPERATURE RATE CONSTANTS AND MODELING OF NH, NH{sub 2}, AND NH{sub 3} ABUNDANCES IN DENSE INTERSTELLAR CLOUDS
- Université de Bordeaux, Institut des Sciences Moléculaires, UMR 5255, F-33400 Talence (France)
- Institut de Physique de Rennes, Astrophysique de Laboratoire, UMR CNRS 6251, Université de Rennes 1, Campus de Beaulieu, F-35042 Rennes Cedex (France)
- Department of Chemistry, West Virginia University, Morgantown, WV 26506 (United States)
- Université de Bordeaux, Laboratoire d’Astrophysique de Bordeaux, UMR 5804, F-33270 Floirac (France)
A continuous supersonic flow reactor has been used to measure rate constants for the C({sup 3}P) + NH{sub 3} reaction over the temperature range 50–296 K. C({sup 3}P) atoms were created by the pulsed laser photolysis of CBr{sub 4}. The kinetics of the title reaction were followed directly by vacuum ultra-violet laser induced fluorescence of C({sup 3}P) loss and through H({sup 2}S) formation. The experiments show unambiguously that the reaction is rapid at 296 K, becoming faster at lower temperatures, reaching a value of (1.8 ± 0.2) × 10{sup −10} cm{sup 3} molecule{sup −1} s{sup −1} at 50 K. As this reaction is not currently included in astrochemical networks, its influence on interstellar nitrogen hydride abundances is tested through a dense cloud model including gas–grain interactions. In particular, the effect of the ortho-to-para ratio of H{sub 2}, which plays a crucial role in interstellar NH{sub 3} synthesis, is examined.
- OSTI ID:
- 22518795
- Journal Information:
- Astrophysical Journal, Vol. 812, Issue 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
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