Repulsion-induced surface-migration, by ballistics and bounce

Guo, S. Y., Jenkins, S. J., Ji, W., Ning, Z., Polanyi, J. C., Sacchi, M. and Wang, C.-G. (2015) Repulsion-induced surface-migration, by ballistics and bounce. Journal of Physical Chemistry Letters, 6 (20). pp. 4093-4098. ISSN 1948-7185 doi: 10.1021/acs.jpclett.5b01829

Abstract/Summary

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 Å 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)