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 whichincludes most of the gas in galactic and extragalactic interstellar clouds.Molecular hydrogen plays a significant role in establishing the thermal balancein many astrophysical environments and can be important as a spectraldiagnostic of the gas. Modeling and interpretation of observations of suchenvironments requires a quantitatively complete and accurate treatment of H2.Using this micro-physical model of H2, illustrative calculations ofprototypical astrophysical environments are presented. This work forms thefoundation for future investigations of these and other environments where H2is an important constituent.