Free Access
Issue
Astron. Astrophys. Suppl. Ser.
Volume 142, Number 1, February II 2000
Page(s) 113 - 118
DOI https://doi.org/10.1051/aas:2000142
Published online 15 February 2000
DOI: 10.1051/aas:2000142

Astron. Astrophys. Suppl. Ser. 142, 113-118

Collisional rates for asymmetrical top molecules[*]

S. Chandra[*] - W.H. Kegel

Send offprint request: W.H. Kegel

Institut für Theoretische Physik der Johann Wolfgang Goethe Universität Frankfurt, Robert-Mayer-Str. 8-10, D-60054 Frankfurt am Main 11, Germany
e-mail: kegel@astro.uni-frankfurt.de

Received May 10; accepted December 13, 1999

Abstract:

Collisional rate coefficients for rotational transitions in C3H2 and SiC2 due to collisions with H2 molecules are calculated. The C3H2 has two distinct species, ortho and para, whereas the SiC2 has only ortho specie due to spin statistics for the identical carbon nuclei. For ortho- and para-C3H2 we accounted for 47 and 48 energy levels, respectively. The calculations are done for the kinetic temperatures 30, 60, 90, and 120 K. For ortho-SiC2, we accounted for 40 energy levels and the calculations are done for the kinetic temperatures 25, 50, 75, 100, and 125 K. The results are reported here for the transitions in the upward direction. The values for the downward direction can easily be calculated with the help of the detailed equilibrium equation.

Key words: ISM: interstellar molecules -- molecular data


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