The C(3P) + NH3 reaction in interstellar chemistry: II. Low temperature rate constants and modeling of NH, NH2 and NH3 abundances in dense interstellar clouds

Abstract

A continuous supersonic flow reactor has been used to measure rate constants for the C + NH3 reaction over the temperature range 50 to 296 K. C atoms were created by the pulsed laser photolysis of CBr4. The kinetics of the title reaction were followed directly by vacuum ultra-violet laser induced fluorescence (VUV LIF) of C loss and through H formation. The experiments show unambiguously that the reaction is rapid at 296 K, becoming faster at lower temperatures, reaching a value of 1.8 10-10 cm3 molecule-1 s-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 H2 which plays a crucial role in interstellar NH3 synthesis is examined.

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• A Kinetic Study of the N(2D) + C2H4 Reaction at Low Temperature
• Experimental and Theoretical Studies of the N(2D) + H2 and D2 Reactions
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• Low-Temperature Kinetics for the N + NO reaction: Experiment Guides the Way
• Sustained oscillations in Interstellar chemistry models
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• Experimental and theoretical studies of the gas-phase reactions of O(${}^1$D) with H${}_2$O and D${}_2$O at low temperature
• Kinetic Study of the Reactions of Ground State Atomic Carbon and Oxygen with Nitrogen Dioxide over the 50-296 K Temperature Range
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