Repulsion-Induced Surface-Migration by Ballistics and Bounce

作者:Guo, Si Yue; Jenkins, Stephen J; Ji, Wei; Ning, Zhanyu; Polanyi, John C*; Sacchi, Marco; Wang, Chen Guang
来源:Journal of Physical Chemistry Letters, 2015, 6(20): 4093-4098.
DOI:10.1021/acs.jpclett.5b01829

摘要

The motion of adsorbate molecules across surfaces is fundamental to self-assembly, material growth, and heterogeneous catalysis. Recent Scanning Tunneling Microscopy studies have demonstrated the electron-induced long-range surface-migration of ethylene, benzene, and related molecules, moving tens of Angstroms across Si(100). We present a model of the previously unexplained long-range recoil of chemisorbed ethylene across the surface of silicon. The molecular dynamics reveal two key elements for directed long-range migration: first 'ballistic' motion that causes the molecule to leave the ab initio slab of the surface traveling 3-8 angstrom above it out of range of its roughness, and thereafter skipping-stone 'bounces' that transport it further to the observed long distances. Using a previously tested Impulsive Two-State model, we predict comparable long-range recoil of atomic chlorine following electron-induced dissociation of chlorophenyl chemisorbed at Cu(110).