A New Mechanism for Surface Diffusion: Motion of a Substrate-Adsorbate Complex

S. J. Stranick, A. N. Parikh, D. L. Allara,* and P. S. Weiss*

Journal of Physical Chemistry 98, 11136 (1994).

We propose a new mechanism for diffusion of surface adsorbates in which motion of the substrate atoms to which the adsorbates are attached results in the motion of the substrate-adsorbate complex. We show an experimental example -- the motion of self-assembled monolayers of CH₃O₂C(CH₂)₁₅SH on gold which we have observed by time-lapse imaging using scanning tunneling microscopy. This mechanism is also used to explain previous data for motion of Cu-O complexes on the Cu{110} surface.