Lyman-Werner photons

A Lyman-Werner photon is an ultraviolet photon with an energy in the range of 11.2 to 13.6 eV, corresponding to the energy range in which the Lyman and Werner absorption bands of molecular hydrogen (H$\_2$) are found. A photon in this energy range with a frequency that coincides with that of one of the lines in the Lyman or Werner bands can be absorbed by H$\_2$, placing the molecule in an excited electronic state. Radiative decay from this excited state occurs rapidly, with roughly 15% of these decays occurring into the vibrational continuum of the molecule, resulting in its dissociation. [cite journal
last = Draine | first = Bruce T. | coauthors = Bertoldi, Frank | journal = ApJ | year = 1996
title = Structure of Stationary Photodissociation Fronts | volume = 468 | pages = 269 | url = http://adsabs.harvard.edu/abs/1996ApJ...468..269D] This two-step photodissociation process, known as the Solomon process, is one of the main mechanisms by which molecular hydrogen is destroyed in the interstellar medium.

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