Berlin 2012 – scientific programme
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O: Fachverband Oberflächenphysik
O 87: Surface chemical reactions
O 87.3: Talk
Friday, March 30, 2012, 11:00–11:15, MA 042
H-atom relay reactions in real space — •takashi kumagai1, hiroshi okuyama2, tetsuya aruga2, ikutaro hamada3, thomas frederiksen4, and hiromu ueba5 — 1Fritz-Haber Institute of the Max-Planck Society — 2Kyoto University — 3Tohoku University — 4Donostia International Physics Center — 5Toyama University
The relay mechanism, in which H-atom transfer occurs in a sequential fashion along hydrogen bonds, plays an essential role in many functional compounds. The scanning tunneling microscope (STM) is used to assemble and control a test-bed for real-space observation of H-atom relay reactions at a single-molecule level. We demonstrate that the transfer of H-atoms along hydrogen-bonded chains assembled on a Cu(110) surface is controllable and reversible, and is triggered by excitation of molecular vibrations induced by inelastic tunneling electrons. The one-dimensional chain complexes consisted of water and hydroxyl groups are constructed in a step-by-step manner using a combination of STM manipulation and controlled dissociation of water molecules. Time-resolved measurement of the H-atom relay enables us to determine the rate as a function of tunneling current and bias voltage. The experimental findings are rationalized by ab initio calculations for adsorption geometry, active vibrational modes and reaction pathway, to reach a detailed microscopic picture of the elementary processes.