Collisional rate coefficients are taken from the litterature and include collisions with: hydrogen (Launay and Roueff 1977), electrons (Johnson et al. 1987), protons (Roueff & Le Bourlot 1990), helium (Staemmler & Flower 1991), and molecular hydrogen (Schröder et al. 1991).
More recent calculations for C-H collisions by Abrahamsson et al (2007) will be provided soon, but the difference with the Launay & Roueff rates is small.

• References
  Johnson, C.T., Burke, P.G., Kingston, A.E. 1987, J.Phys.B, 20, 2553
  Launay, J.M. & Roueff, E. 1977, J.Phys.B, 10, 879
  Roueff, E. & Le Bourlot, J. 1990, A&A, 236, 515
  Schröder, K., Staemmler, V., Smith, M. D., Flower, D. R., & Jacquet, R. 1991, J.Phys.B., 24, 2487
  Staemmler, V. & Flower, D.R. 1991, J.Phys. B, 24, 2343