Regensburg 2016 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 73: Surface Dynamics: Reactions and Elementary Processes
O 73.15: Poster
Mittwoch, 9. März 2016, 18:15–20:30, Poster A
XUV photochemistry of CO and 13CD3OD ice mixtures on HOPG — •Tushar Suhasaria, John Thrower, Robert Frigge, Sebastian Roling, and Helmut Zacharias — Physikalisches Institut, Universität Münster, Germany
In the interstellar medium (ISM), photochemical reactions occur on the surface of dust grains. In cold regions the grains are covered by mixed molecular ices. In these ice matrices, high-energy radiation from young stars leads to the formation of new molecules. On a cold (ca. 15 K) highly-oriented pyrolytic graphite (HOPG) surface, a mixture of CO and 13CD3OD was irradiated by 30.4 nm femtosecond XUV pulses from the Free-electron laser in Hamburg (FLASH). The resulting desorption products were identified by time-of-flight mass spectrometry and are dominated by low mass fragment ions from the adsorbed molecules along with some higher mass clusters. In addition, a (2+1) resonance enhanced multi-photon ionization (REMPI) scheme via the B1Σ ← X1Σ transition of CO molecules at 230 nm was used to probe the internal energy content of desorbing neutral CO. The desorbing ions and neutral products show a non-linear intensity dependence which allows the determination of the reaction dynamics by two-pulse correlation measurements.