Investigations of Desorption of Hydrogen from Low Temperature Surfaces of Silicates
We report on experimental investigations of HD production on low temperature surfaces of silicates under conditions relevant to hydrogen recombination on dust grain surfaces in the interstellar medium. Following adsorption of H and D at thermal energies on a silicate surface (olivine) in the 5–15 K range, flash desorption experiments were conducted to yield desorption energies and order of desorption kinetics. We find that significant recombination occurs only at the lowest temperatures. Current models of diffusion and recombination of H on cold surfaces, developed to explain interstellar recombination processes, will be discussed and appraised in the light of the new results.
KeywordsInterstellar Medium Interstellar Cloud Desorption Kinetic Tunneling Time Recombination Coefficient
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