Photodissociation of N2

This webpage is intended to be used in conjunction with the papers by Li et al. (2013, A&A, 555, A14) and Heays et al. (2014, A&A, 562, A61) containing detailed descriptions of how the shielding functions presented below were derived and how they should be used. If you publish anything based on these data, please be sure to cite these as follows:

Li, X., Heays, A.N., Visser, R., Ubachs, W., Lewis, B.R., Gibson, S.T., & van Dishoeck, E.F., Astronomy & Astrophysics, 555, A14 [Publisher, arXiv full text]

Heays, A. N., Visser, R., Gredel, R., Ubachs, W., Lewis, B. R., Gibson, S. T. & van Dishoeck, E. F. Astronomy & Astrophysics (2014), 562:A61 [Publisher, arXiv full text]

Cross sections

These cross sections assume an N2 excitation temperature of 100 K and a Doppler broadening of 1 km s-1.

Shielding functions

Shielding functions are available here for 14N2 and 14N15N for several sets of parameters. Doppler widths are given as 2-sigma widths. There is a fixed elemental ratio in all cases, 14N:15N = 450:1 or 14N2:14N15N = 225:1).

[Download all shielding functions as an archive.]

  1. Individual Files in this archive contain shielding function for a particular excitation temperature (Tex), H2 linewidth (bH2), atomic-H linewidth (bH), and fixed atomic-H column-density (NH).
  2. Each file contains shielding functions over a grid of 14N2 and H2 column densities. A separate grid is given for 14N15N shielding functions, in which case the dominant shielding is still due to 14N2 and H2. The range of 14N2 and H2 column densities are listed before the grid arrays.