Berlin 2012 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 87: Surface chemical reactions
O 87.5: Vortrag
Freitag, 30. März 2012, 11:30–11:45, MA 042
Front dynamics in the O2 + NH3 reaction on Rh(110) surfaces investigated with LEEM — •Benjamin Borkenhagen1, Mathías Rafti2,3, Gerhard Lilienkamp1, Winfried Daum1, and Ronald Imbihl3 — 1Institut für Energieforschung und physikalische Technologien, TU-Clausthal, Leibnizstraße 4, D-38678 Clausthal-Zellerfeld — 2Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas (INIFTA), Fac. Cs. Exactas, Universidad Nacional de La Plata. 64 y Diag. 113 (1900) La Plata, Argentina — 3Institut für Physikalische Chemie und Elektrochemie, Leibniz-Universität Hannover, Callinstraße 3-3a, D-30167 Hannover
Recent research on the O2 + NH3 reactions on Rh(110) focused on interface instabilities in this bistable reaction system. Since the surface structures and changes in the surface anisotropy presumably play a central role in the mechanism of the front instabilities we studied this reaction system in the 10−6 and 10−5 mbar range with LEEM (low energy electron microscopy) and µLEED. We identified the mixed coadsorbate phase c(2×4)-O,N and the c(2×6)-O phase in the bistable range. At higher temperatures we discovered the formation of µm-sized islands and studied phase transitions on these islands in detail. The phase transition front breaks up into separate fronts on each island. The small fronts are mainly influenced by the microscopic surface structure such as surface steps.