Energy levels, transition frequencies and Einstein A coefficients were taken from CDMS. The collisional rates are taken from Green (1991) and were calculated for temperatures in the range from 10 to 300 K including energy levels up to about 200 cm^-1 for collisions with He. This data set was scaled by 1.37 to make a first order approximation for collisions with H₂.

For the specific case of H₂CO, Green (1991) refers to collision broadening studies by Nerf (1975) which indicate that as a second order effect, the rates should be multiplied by 2.2 to also account for the larger cross section of H₂ relative to He. The datafiles do not include this scale factor to keep the database homogeneous, but users may apply the additional factor 1.6 themselves.

• References
  Green, S. 1991, ApJS, 76, 979
  Nerf, R.B. 1975, J. Mol. Spec. 58, 451