2065 20160701171658.0 10.1086/429215 DOI ASTROimport-222 Shaw, G. 2005 Molecular Hydrogen in Star-forming Regions: Implementation of its Microphysics in CLOUDY Much of the baryonic matter in the universe is in the form of H2, which includes most of the gas in Galactic and extragalactic interstellar clouds. Molecular hydrogen plays a significant role in establishing the thermal balance in many astrophysical environments and can be important as a spectral diagnostic of the gas. Modeling and interpretation of observations of such environments requires a quantitatively complete and accurate treatment of H2. Using this microphysical model of H2, we present illustrative calculations of prototypical astrophysical environments. This work forms the foundation for future investigations of these and other environments in which H2 is an important constituent. Ferland, G. J. Abel, N. P. Stancil, P. C. van Hoof, P. A. M. The Astrophysical Journal 624 2 2005 794-807 http://esoads.eso.org/abs/2005ApJ...624..794S published in REFERD