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Title: The C(3P) + NH3 reaction in interstellar chemistry. I. Investigation of the product formation channels

The product formation channels of ground state carbon atoms, C(3P), reacting with ammonia, NH3, have been investigated using two complementary experiments and electronic structure calculations. Reaction products are detected in a gas flow tube experiment (330 K, 4 Torr) using tunable vacuum-ultraviolet (VUV) photoionization coupled with time of flight mass spectrometry. Temporal profiles of the species formed and photoionization spectra are used to identify primary products of the C + NH3 reaction. In addition, H-atom formation is monitored by VUV laser induced fluorescence (LIF) from room temperature to 50 K in a supersonic gas flow generated by the Laval nozzle technique. Electronic structure calculations are performed to derive intermediates, transition states, and complexes formed along the reaction coordinate. The combination of photoionization and LIF experiments supported by theoretical calculations indicate that in the temperature and pressure range investigated, the H + H2CN production channel represents 100% of the product yield for this reaction. As a result, kinetics measurements of the title reaction down to 50 K and the effect of the new rate constants on interstellar nitrogen hydride abundances using a model of dense interstellar clouds are reported in Paper II.
Authors:
 [1] ;  [1] ;  [2] ;  [3] ;  [4] ;  [4] ;  [5] ;  [2] ;  [1]
  1. UMR, CNRS 6251, Univ. de Rennes, Rennes Cedex (France)
  2. West Virginia Univ., Morgantown, WV (United States)
  3. Sandia National Lab. (SNL-CA), Livermore, CA (United States)
  4. Univ. de Bordeaux, Talence (France); CNRS, Institut des Sciences Moleculaires, Talence (France)
  5. Univ. Bordeaux, Floirac (France); CNRS, LAB, UMR, Floirac (France)
Publication Date:
OSTI Identifier:
1329618
Report Number(s):
SAND--2016-10072J
Journal ID: ISSN 1538-4357; 648108
Grant/Contract Number:
AC04-94AL85000
Type:
Accepted Manuscript
Journal Name:
The Astrophysical Journal (Online)
Additional Journal Information:
Journal Name: The Astrophysical Journal (Online); Journal Volume: 812; Journal Issue: 2; Journal ID: ISSN 1538-4357
Publisher:
Institute of Physics (IOP)
Research Org:
Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
79 ASTRONOMY AND ASTROPHYSICS astrochemistry; ISM: atoms; ISM: clouds; ISM: molecules: molecular data; molecular processes