Energy levels, transition frequencies and Einstein A coefficients were taken from CDMS. The collisional rate coefficients are taken to be the same as for HCO⁺ and include energy levels up to J=30 and temperatures from 10 to 2000 K. For details on the extrapolation see Schöier et al. (2005).

• References
  Schöier, F.L, van der Tak, F.F.S., van Dishoeck, E.F., Black, J.H. 2005, A&A 432, 369