Molecular hydrogen formation on astrophysically relevant surfaces

N. Katz*, I. Furman, O. Biham, V. Pirronello, G. Vidali

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

288 Scopus citations

Abstract

Recent experimental results about the formation of molecular hydrogen on astrophysically relevant surfaces under conditions close to those encountered in the interstellar medium are analyzed using rate equations. The parameters of the rate equation model are fitted to temperature-programmed desorption curves obtained in the laboratory. These parameters are the activation energy barriers for atomic hydrogen diffusion and desorption, the barrier for molecular hydrogen desorption, and the probability of spontaneous desorption of a hydrogen molecule upon recombination. The model is a generalization of the Polanyi-Wigner equation and provides a description of both first- and second-order kinetic processes within a single model. Using the values of the parameters that best fit the experimental results, the efficiency of hydrogen recombination on olivine and amorphous carbon surfaces is obtained for a range of hydrogen flux and surface temperature pertinent to a wide range of interstellar conditions.

Original languageAmerican English
Pages (from-to)305-312
Number of pages8
JournalAstrophysical Journal
Volume522
Issue number1 PART 1
DOIs
StatePublished - 1 Sep 1999

Keywords

  • Dust, extinction
  • ISM: abundances
  • ISM: molecules
  • Molecular processes

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