Regensburg 2025 – scientific programme
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O: Fachverband Oberflächenphysik
O 31: Focus Session Molecular Nanostructures on Surfaces: On-Surface Synthesis and Single-Molecule Manipulation II
O 31.4: Talk
Tuesday, March 18, 2025, 11:30–11:45, H24
How to measure cones of reaction for single-molecule collisions — •Matthew J. Timm1, Stefan Hecht2, and Leonhard Grill1 — 1Institute of Chemistry, University of Graz, Austria — 2Department of Chemistry & IRIS Adlershof, Humboldt-Universität zu Berlin, Germany
Collisions between reagents are necessary for bond formation, and hence fundamental to reaction. The collision outcome depends on the collision energy, which must be enough to overcome the reaction barrier, and on the collision geometry, which modifies the height of this barrier. The collision geometry is defined by the relative orientation of reagents at the point of collision and on the miss-distance between their centers of mass (termed the impact parameter). Selection of impact parameter has been demonstrated for on-surface reactions with a 'surface-molecular-beam' of CF2 'projectiles', formed by dissociation of chemisorbed CF3 molecules with a scanning tunneling microscope tip, aimed along Cu-rows of the Cu(110) surface toward chemisorbed 'targets' [1]. However, control over the relative orientation of the target has remained elusive. Here a singly-debrominated molecular species (BTFyl) is chosen as a target, as it adopts many possible adsorption alignments relative to the incoming CF2 projectile. This allows simultaneous control over both the impact parameter and reagent orientation, thus allowing an unprecedented ability to map how collision geometry contributes to collision outcome.
[1] Anggara, K.; Leung, L.; Timm, M. J.; Hu, Z.; Polanyi, J. C.; Faraday Discuss., 2019, 214, 89-103.
Keywords: Surface-Aligned Reaction; surface-molecular beam; selected impact parameter; selected reagent alignment; scanning tunneling microscopy