PHYS 596 |
| The interstellar reaction of ground-state carbon atom with the second member of polyyne family, triacetylene (HCCCCCCH), is investigated theoretically to explore probable routes to form hydrogen-deficient carbon clusters at ultra-low temperature in cold molecular clouds. The isomerization and decomposition channels on C7H2 adiabatic triplet ground-state potential energy surface for each of the five collision complexes are characterized by utilizing the unrestricted B3LYP/6-311G(d,p) level of theory and the CCSD(T)/cc-pVTZ calculations. With facilitation of RRKM and variational RRKM rate constants at collision energies of 0-10 kcal/mol, the most probable paths, thus reaction mechanism, are determined amid over one hundred intermediates and more than a dozen dissociation products. The corresponding rate equations are then solved such that the evolutions of concentrations of collision complexes, intermediates, and products versus time are obtained. As a result, the final products and yields are identified. This study predicts that five collision complexes, c1-c5, would produce a single final product, carbon chain C7H + H. Our investigation indicates the title reaction is efficient to form astronomically observed C7H in cold molecular clouds. |
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PHYS Poster Session - Computational Spectroscopy and Reaction Dynamics
7:30 PM-10:00 PM, Wednesday, April 9, 2008 Morial Convention Center -- Hall A, Poster
Sci-Mix
Division of Physical Chemistry |