Energy levels, transition frequencies and Einstein A coefficients were taken from JPL. 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).

We also provide a file with recent coefficients by Daniel et al (2005) which include the hyperfine structure of N₂H⁺. The spectroscopic data for this datafile come from the CDMS catalog.

• References
  Schöier, F.L, van der Tak, F.F.S., van Dishoeck, E.F., Black, J.H. 2005, A&A 432, 369
  Daniel, F., Dubernet, M.-L., Meuwly, M., Cernicharo, J., Pagani, L. 2005, MNRAS 363, 1083