Regensburg 2022 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 69: Surface Reactions and Heterogeneous Catalysis 2

O 69.2: Vortrag

Donnerstag, 8. September 2022, 15:30–15:45, H4

Why interlayer exchange is crucial for temperature programmed desorption — •Tobias Dickbreder, Ralf Bechstein, and Angelika Kühnle — Physical Chemistry I, Bielefeld University, Universitätstraße 25, 33615 Bielefeld

Understanding the desorption of molecules from surfaces is fundamental for both natural and application-oriented processes such as dewetting, weathering and catalysis. A powerful method to investigate desorption processes is temperature programmed desorption (TPD) as it offers the possibility to gain mechanistic insights into the desorption kinetics. In the past, several analysis methods have been developed for TPD data. These methods have in common that they rely on the Polanyi-Wigner equation, which requires proposing a desorption mechanism with a single (dominating) desorption path. For real systems, however, several coupled desorption paths can be easily envisioned. Here, we analyze the influence of exchange between the first and the second adsorbate layer on the desorption process. We show that considering this additional desorption pathway alters the desorption spectrum considerably. Thus, our study demonstrates that interlayer exchange can be crucial for the analysis of TPD data.