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Author Kaiser, R. I. ♦ Ochsenfeld, C. ♦ Head-Gordon, M. ♦ Lee, Y. T.
Source United States Department of Energy Office of Scientific and Technical Information
Content type Text
Language English
Subject Keyword CHEMISTRY ♦ ORGANIC COMPOUNDS ♦ RADICALS ♦ GROUND STATES ♦ CARBON ♦ HYDROGEN SULFIDES ♦ CHEMICAL REACTION KINETICS ♦ TIME-OF-FLIGHT METHOD ♦ ATOMIC BEAMS ♦ MOLECULAR BEAMS ♦ ORGANIC SULFUR COMPOUNDS
Abstract The reaction between ground state carbon atoms, C({sup 3}P{sub j}), and hydrogen sulfide, H{sub 2}S(X{sup 1}A{sub 1}), was studied at four average collision energies between 16.7 and 42.8 kJ mol{sup {minus}1} using the crossed molecular beam technique. The reaction dynamics were deducted from time-of-flight spectra and from laboratory angular distributions combined with {ital ab initio} calculations. These data suggest that the reaction proceeds through an addition of C({sup 3}P{sub j}) to the sulfur atom to form a triplet CSH{sub 2} van der Waals complex. Successive H atom migration on the triplet or singlet surface forms a thiohydroxycarbene intermediate, HCSH, which decomposes through a tight exit transition state to HCS(X{sup 2}A{sup {prime}})+H({sup 2}S{sub 1/2}). At lower collision energies, a weak {bold L-L}{sup {prime}} coupling leads to isotropic center-of-mass angular distributions. As the collision energy rises, the angular distributions show increasing forward scattering thereby documenting that the reaction goes through an osculating HCSH complex. Identification of the HCS isomer under single collision conditions is a potential one-step pathway by which to form organo-sulfur molecules in interstellar environments during the collision of the comet Shoemaker-Levy 9 with Jupiter, and in combustion flames of sulfur containing fuels. {copyright} {ital 1999 American Institute of Physics.}
ISSN 00219606
Educational Use Research
Learning Resource Type Article
Publisher Date 1999-02-01
Publisher Place United States
Journal Journal of Chemical Physics
Volume Number 110
Issue Number 5


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