### Abstract

Cross sections and rate coefficients for CN+H_{2} collisions are calculated using the coupled states (CS) approximation. The calculations are benchmarked against more accurate close-coupling (CC) calculations for transitions between low-lying rotational states. Comparisons are made between the two formulations for collision energies greater than 10 cm^{−1}. The CS approximation is used to construct a database which includes highly excited rotational states that are beyond the practical limitations of the CC method. The database includes fine-structure resolved rotational quenching transitions for v=0 and j ≤ 40, where v and j are the vibrational and rotational quantum numbers of the initial state of the CN molecule. Rate coefficients are computed for both para-H_{2} and ortho-H_{2} colliders. The results are shown to be in good agreement with previous calculations, however, the rates are substantially different from mass-scaled CN+He rates that are often used in astrophysical models.

Original language | English (US) |
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Pages (from-to) | 23-32 |

Number of pages | 10 |

Journal | Molecular Astrophysics |

Volume | 11 |

DOIs | |

State | Published - Jun 2018 |

### All Science Journal Classification (ASJC) codes

- Astronomy and Astrophysics
- Spectroscopy
- Physical and Theoretical Chemistry
- Space and Planetary Science

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## Cite this

_{2}collisions.

*Molecular Astrophysics*,

*11*, 23-32. https://doi.org/10.1016/j.molap.2018.03.001