Directed long-range molecular migration energized by surface reaction
Author: ["K. R. Harikumar","John C. Polanyi","Amir Zabet-Khosousi","Piotr Czekala","Haiping Lin","Werner A. Hofer"]
Publication: Nature Chemistry
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Abstract
The recoil of adsorbates away (desorption) and towards (reaction) surfaces is well known. Here, we describe the long-range recoil of adsorbates in the plane of a surface, and accordingly the novel phenomenon of reactions occurring at a substantial distance from the originating event. Three thermal and three electron-induced surface reactions are shown by scanning tunnelling microscopy to propel their physisorbed ethylenic products across the rough surface of Si(100) over a distance of up to 200 Å before an attachment reaction. The recoil energy in the ethylenic products comes from thermal exoergicity or from electronic excitation of chemisorbed alkenes. We propose that the mechanism of migration is a rolling motion, because the recoiling molecule overcomes raised surface obstacles. Electronic excitation of propene causes directional recoil and often end-to-end inversion, suggesting cartwheeling. Ab initio calculations of the halogenation and electron-induced reactions support a model in which asymmetric forces between the molecule and the surface induce rotation and therefore migration. The recoil of adsorbates away from and towards surfaces is well-known. Here, long-range recoil in the plane of the surface, which leads to reaction at a distance, is described. Surface reactions are shown to propel their physisorbed ethylenic products across the rough surface of Si(100) by up to 200 Å before re-attachment.
Cite this article
Harikumar, K., Polanyi, J., Zabet-Khosousi, A. et al. Directed long-range molecular migration energized by surface reaction. Nature Chem 3, 400–408 (2011). https://doi.org/10.1038/nchem.1029
