Collisional rates for asymmetrical top molecules
Abstract
Collisional rate coefficients for rotational transitions in C_3H_2 and SiC_2 due to collisions with H_2 molecules are calculated. The C_3H_2 has two distinct species, ortho and para, whereas the SiC_2 has only ortho specie due to spin statistics for the identical carbon nuclei. For ortho- and para-C_3H_2 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-SiC_2, 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. Tables 3A, 3B, 3C, 3D, 4A, 4B, 4C, 4D, 5A, 5B, 5C, 5D and 5E are available only in electronic form via anonymous ftp (130.79.128.5) at the CDS to cdsarc.u-strasbg.fr or via http://cdsweb.u-strabg.fr/Abstract.html
- Publication:
-
Astronomy and Astrophysics Supplement Series
- Pub Date:
- February 2000
- DOI:
- 10.1051/aas:2000142
- Bibcode:
- 2000A&AS..142..113C
- Keywords:
-
- ISM: INTERSTELLAR MOLECULES;
- MOLECULAR DATA