Fine-structure Resolved Rotational Transitions and Database for CN+H2 Collisions
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Cross sections and rate coefficients for CN+H2 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 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-H2 and ortho-H2 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.
Log-derivative method; Cross-sections; Scattering; CN; Excitation
Forrey, R. C.,
Yang, B. H.,
Stancil, P. C.,
Fine-structure Resolved Rotational Transitions and Database for CN+H2 Collisions.
Molecular Astrophysics, 11