Regensburg 2022 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 69: Surface Reactions and Heterogeneous Catalysis 2

O 69.6: Vortrag

Donnerstag, 8. September 2022, 16:30–16:45, H4

On-surface collision reactions — •Matthew J. Timm, Kelvin Anggara, Lydie Leung, Zhixin Hu, and John C. Polanyi — Lash Miller Chemical Laboratories, Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, Ontario M5S 3H6, Canada

Collisions between atoms and molecules are required for forming chemical bonds, thus they are central to any chemical reaction. The outcome of these collisions depends on the collision energy, geometry, and miss-distance between centers of the colliding reagents (called the impact parameter). As the incoming species - in general - randomly misses the target's center of mass, measurement of the impact parameter is a long-standing problem. Recently, a 'surface-molecular-beam' approach has been demonstrated that can allow for selection of impact parameter in a surface-reaction [1-3]. Energetic, oppositely-recoiling CF2 or F-atom "projectiles" are formed on a Cu(110) surface by dissociation of chemisorbed CF3 molecules with the tip of a Scanning Tunneling Microscope (STM). The inherent corrugation of Cu(110) leads to collimated trajectories of these projectiles, allowing them be aimed to collide with nearby molecular "targets" at chosen impact parameters. The pattern of reactive and non-reactive scattering was then determined by STM with the dynamics of the collision elucidated by density functional theory calculations.

[1] Anggara, K.; Leung, L.; Timm, M. J.; Hu, Z.; Polanyi, J. C.; Sci Adv., 2018, 4, eaau2821. [2] Anggara, K.; Leung, L.; Timm, M. J.; Hu, Z.; Polanyi, J. C.; Faraday Discuss., 2019, 214, 89-103. [3] Leung, L.; Timm, M. J.; Polanyi, J. C.; Chem. Commun., 2021, 57, 12647-12650.