Using scanning tunneling microscopy, we have investigated the step dynamics
on an Au(lll) single crystal electrode in aqueous electrolytes. Our studie
s focused on the influence of specifically adsorbed anions and the anion co
ncentration on the mobility of gold atoms at monatomic-high step edges. The
experiments were performed in chloride-containing and chloride-free H2SO4
electrolytes. From the quantitative analysis of equilibrium step fluctuatio
ns we deduce the dominant mass transport mechanisms as a function of the el
ectrode potential and as a function of the anion concentration. Estimates o
f the energies involved in the mass transport are presented. (C) 2000 Elsev
ier Science B.V. All rights reserved.