Reconstruction of Au(111) following the reductive desorption of self-assembled monolayers of 2-mercaptoethanesulfonic acid studied by in situ scanning tunneling microscopy

The reconstruction of Au(111) to (root3 x 23) structure after the reductive desorption of a self-assembled monolayer (SAM) composed of 2-mercaptoethan esulfonic acid (MESA) has been imaged by in situ scanning tunneling microsc opy (STM) in a 0.5 mol dm(-3) KOH aqueous solution. The STM images dearly s how that after the reductive desorption of MESA the Au(111) surface reconst ructs to the (root3 x 23) structure. The reconstruction starts from the edg e, spreads gradually, and covers the entire terraces of Au(111) on the time scale of several minutes. Pits of the gold substrate are formed especially at the boundaries between the unreconstructed and the reconstructed areas during the spread of the reconstruction.