HCN
Hydrogen cyanide
LAMDA | RADEX on-line

Energy levels, transition frequencies and Einstein A coefficients were taken from CDMS version 4 of May 2007. Collisional rate coefficients are from Dumouchel et al (2010) who have also made calculations for HNC. The set of rate coefficients was scaled by a factor 1.37 to represent collisions with H2. Electron collision rates are taken from Faure et al (2007) and cover the levels up to J=8 for temperatures from 5 to 800 K.

We also provide older collisional calculations from Green & Thaddeus (1974) and Green (unpublished data), extrapolated for the temperature range from 5 to 1200 K, and including energy levels up to J=29. for collisions with He. This dataset may still be useful to model high-J line observations of HCN. For details on the extrapolation see Schöier et al. (2005).

The third datafile takes the hyperfine splitting (hfs) of the levels up to J=10 into account. Collision data with H2 for temperatures from 5 to 100 K are taken from Ben Abdallah et al (2012).


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