15.05.2006 |
Recombination pathways and energy release in molecular hydrogen formation on graphite surfaces: Implications for interstellar H2 formation
Liv Hornekær,Department of Physics and Astronomy, University of Aarhus, Denmark
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The adsorption and recombination of atomic hydrogen on graphite surfaces has attracted considerable interest both in connection with hydrogen storage and in connection with astrochemistry. By combining Scanning Tunnelling Microscopy (STM) measurements and Density Functional Theory calculations we have identified the adsorption structures and recombination pathways for atomic hydrogen on graphite. We show that at low coverage atomic hydrogen forms dimers on the graphite surface due to preferential sticking. Recombination takes place out of only one of two pre-paired hydrogen dimer states. Laser desorption techniques allow us to measure the time of flight spectra for hydrogen molecules formed on the graphite surface and thereby to determine the energy partitioning into kinetic energy of the formed molecules. The implications of these findings for interstellar H2 formation will be discussed.
Einladender: Prof. Dr. H. Zacharias
| Ort: |
Wilhelm-Klemm-Str. 9, Raum 404 |
| Zeit: |
montags 17 Uhr c.t. |
Im Auftrag der Hochschullehrer des Fachbereichs Physik
Prof. Dr. S. Demokritov
