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.

• ¹⁴N₂ cross sections in binary/hdf5 format
• ¹⁴N₂ cross sections in text format
• ¹⁴N¹⁵N cross sections in binary/hdf5 format
• ¹⁴N¹⁵N cross sections in text format

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.