Regensburg 2013 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 36: Poster Session II (Organic films and electronics, photoorganics; Nanostructures; Plasmonics and nanooptics, Surface chemical reactions and heterogeneous catalysis, Surface dynamics )
O 36.86: Poster
Dienstag, 12. März 2013, 18:15–21:45, Poster B2
Thermal desorption spectroscopy of astrophysically relevant molecules on olivine and single crystal forsterite — •Tushar Suhasaria1,2, Nadine Heming1, Robert Frigge1, Björn Siemer1, and Helmut Zacharias1,2 — 1Physikalisches Institut, University of Münster, Germany — 2Graduate School of Chemistry, University of Münster, Germany
Over the years, it has been known that gas-grain chemistry is responsible for molecule formation in the interstellar medium [1]. These dust grains are thought to be silicates or carbonaceous materials. In recent times more than 140 different gases have been reported in the dense regions of interstellar space [2]. At low temperatures (≈ 10 K) in the ISM the icy grain mantles undergo processing and are forming molecules due to exposure to ultraviolet, x-ray, cosmic radiation and heat. Temperature programmed desorption (TPD) is the most widely used characterization technique to investigate these primary effects and provide binding energies and reaction orders .Starting at 4K we performed TPD measurements on several molecules like D2, CO, CH4,CO2 and NH3 adsorbed on single crystal forsterite (MgSiO4) and olivine ( Mgx Fe1−x SiO4) surfaces. Averaging over several measurements, it is seen that D2, CO, CH4, CO2 molecules have slightly greater average binding energies on forsterite than on olivine.
1] D. A. Williams, E. Herbst, Surf. Sci. 500, 823, (2002).
2] D. J. Burkew, W. A. Brown, Phys. Chem. Chem. Phys. 12, 5947-5969, (2010).