Structure sensitive reaction channels of molecular hydrogen on silicon surfaces

Reviews and Highlights	Quantum Science	Molecular and Soft-matter	Ultrafast Nano-optics and Nanophotonics	Mineralogy and Geochemistry

Michael Dürr, Markus B. Raschke, Eckhard Pehlke, and Ulrich Höfer
Phys. Rev. Lett. 86, 123 (2001).
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The ability of the Si(001) surface to adsorb H₂ molecules dissociatively increases by orders of magnitude when appropriate surface dangling bonds are terminated by H atoms. Through molecular beam techniques the energy dependent sticking probability at different adsorption sites on H-precovered and stepped surfaces is measured to obtain information about the barriers to adsorption, which decrease systematically with an increase in coadsorbed H atoms. With the help of density functional calculations for interdimer adsorption pathways, this effect is traced back to the electronic structure of the different adsorption sites and its interplay with local lattice distortions.