Berlin 2024 – scientific programme
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O: Fachverband Oberflächenphysik
O 34: Poster: Surface Dynamics & Electron-Driven Processes
O 34.4: Poster
Tuesday, March 19, 2024, 18:00–20:00, Poster C
Power discontinuity and shift of the energy onset of a molecular de-bromination reaction induced by hot-electron tunneling — Ana Barragan1, Roberto Robles2, Nicolas Lorente2,4, and •Lucia Vitali1,2,3,4 — 1Advanced Polymers and Materials: Physics, Chemistry and Technology, Chemistry Faculty (UPV/EHU) — 2Centro de Física de Materiales CFM/MPC(CSIC-UPV/EHU), — 3Ikerbasque Research Foundation for Science, Bilbao 48009, Spain; — 4Donostia International Physics Center (DIPC), 20018 San Sebastián,
Understanding the mechanism of molecular dissociation under applied bias is a fundamental requirement to progress in (electro)- catalysis as well as in (opto)-electronics. The working conditions of a molecular-based device and the stability of chemical bonds can be addressed in metal-organic junctions by injecting electrons in tunneling conditions. Here, we have correlated the energy of debromination of an aryl group with its density of states in a self-assembled dimeric structure of 4'-bromo-4-mercaptobiphenyl adsorbed on a Au(111) surface. We have observed that the electron-energy range where the molecule is chemically stable can be extended, shifting the bias threshold for the rupture of the -C-Br bond continuously from about 2.4 to 4.4 V by changing the electron current. Correspondingly, the power needed for the dissociation drops sharply at 3.6 V, identifying different reaction regimes and the contribution of different molecular resonance states.
Keywords: Electron induced process; Conductance channels