About this website

Photodissociation and photoionization are major destruction processes of molecules in any astrophysical region where ultraviolet photons penetrate, including diffuse and translucent clouds, dense PDRs, the surface layers of protoplanetary disks, and cometary and exoplanetary atmospheres.

This website provides the basic molecular data needed to compute photodestruction rates in various environments, with references to the original sources of the cross section data. Only species for which laboratory or theoretical data are available have been included. Overview papers papers describing the methods, cross section data and an assessment of the accuracy of the photorates are provided.

What can I find here?

  1. Atomic and molecular photoabsorption, photodissociation, and photoionisation cross sections in numerical form.
  2. Figures displaying the cross sections.
  3. Photo rates for various stellar radiation fields and for cosmic-ray induced radiation.
  4. Depth-dependent shielding functions
  5. Additional detailed data on N2 and CO isotopologues.
  6. Data on the photodissociation fragment branching ratios of H2O and NH3.
  7. Data on the photodesorption of H2O from interstellar ices.
  8. References for the sources of data and some overview paper describing the website contents.

Contact information

For questions about cross sections or the website please contact Ewine van Dishoeck, or Helgi Rafn Hrodmarsson.


When using material from this site, please cite one of the overview papers. In cases of specific molecules, please cite the original source of the cross sections as appropriate.