A New Phase of the Au(111) Surface in Electrolyte Revealed by STM and Asymmetric Potential Pulse Perturbation.

Asymmetric potential pulse perturbations were combined with STM to separately the (22$\times \sqrt 3 ) \quad \leftrightarrow $ (1$\times $1) phase transition from the dynamics of the dynamics of nanoscale island growth and dissolution at Au(111)/0.1M HClO$_{4}$ interfaces. In the course of these experiments a new surface phase, characterized by a gas of highly mobile Au adatoms on the surface, the absence of islands and a paucity of reconstruction stripes, was observed. This phase coexists with a low density of reconstructed stripes in ``holes''. This new phase is an intermediate state and can only be observed over a potential range range from 0.3 V$_{SCE}$ to 0.45V$_{SCE}$, after a potential pulse lifting the reconstruction. In addition, and contrary to previous reports, the(1$\times $1) $\diamondsuit $ (22$\times \sqrt 3 )$ reconstruction process can be fast.