منابع مشابه
Molecular hydrogen formation in the interstellar medium
We have developed a model for molecular hydrogen formation under astrophysically relevant conditions. This model takes fully into account the presence of both physisorbed and chemisorbed sites on the surface, allows quantum mechanical diffusion as well as thermal hopping for absorbed H-atoms, and has been benchmarked versus recent laboratory experiments on H2 formation on silicate surfaces. The...
متن کاملMolecular hydrogen in the diffuse interstellar medium at high redshift
The physical conditions within damped Lyα systems (DLAs) can reveal the star formation history, determine the chemical composition of the associated ISM, and hence document the first steps in the formation of present day galaxies. Here we present calculations that self-consistently determine the gas ionization, level populations (atomic fine-structure levels and rotational levels of H2), grain ...
متن کاملThe Formation of Molecular Hydrogen in the Interstellar Medium
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متن کاملMolecular Hydrogen Formation During Dense Interstellar Cloud Collapse
We study the evolution of molecular hydrogen on the grain surfaces and in the gas phase using both the rate equation (which tracks the average number of molecules) and the master equation (which tracks the expectation values of molecules). We show that above a certain critical accretion rate of H on the grains, the results from these two methods become identical. We used this result to follow t...
متن کاملMolecular Hydrogen Formation on Amorphous Silicates Under Interstellar Conditions
Experimental results on the formation of molecular hydrogen on amorphous silicate surfaces are presented for the first time and analyzed using a rate equation model. The energy barriers for the relevant diffusion and desorption processes are obtained. They turn out to be significantly higher than those obtained earlier for polycrystalline silicates, demonstrating the importance of grain morphol...
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ژورنال
عنوان ژورنال: Symposium - International Astronomical Union
سال: 1970
ISSN: 0074-1809
DOI: 10.1017/s0074180900102219