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O: Fachverband Oberflächenphysik
O 16: Surface Dynamics & Electron-Driven Processes
O 16.8: Talk
Monday, March 18, 2024, 16:45–17:00, MA 141
How a long-range attraction influences desorption kinetics — •Florian Schneider1, Lukas Höltkemeier1, Andrea Floris2, Lev Kantorovich3, Ralf Bechstein1, and Angelika Kühnle1 — 1Physical Chemistry I, Bielefeld University, 33615 Bielefeld, Germany — 2School of Chemistry, University of Lincoln, Brayford Pool, Lincoln LN6 7TS, UK — 3Department of Physics, Kings's College London, London WC2R 2LS, UK
Desorption of molecules from surfaces is omnipresent both in nature and technology. Despite its omnipresence and conceptual simplicity, fundamental details can be surprisingly complex and are often poorly understood. Here, we study the desorption of a submonolayer film of 3-nitrophenol from the natural cleavage plane of calcite kept in ultrahigh vacuum. Interestingly, two distinctly different desorption regimes are observed during isothermal desorption monitored by dynamic atomic force microscopy. Initially, at high coverages, the coverage decreases almost linearly in time, indicating a constant desorption rate. Beyond this linear regime, at low coverages, a drastic increase in desorption rate is observed until the surface is completely empty. The transition between these two regimes is associated with a critical island width. The increase in desorption rate when falling below a critical island width indicates that a long-range attractive interaction between the molecules is present. The herein observed phenomenon of two different desorption regimes is expected to be of general significance when interactions beyond next-neighbor attraction are present.
Keywords: Desorption; Atomic-force microscopy; long-range interaction