INSITU OBSERVATION OF MONOLAYER STRUCTURES OF UNDERPOTENTIALLY DEPOSITED HG ON AU(111) WITH THE ATOMIC FORCE MICROSCOPE

The structures of monolayers of Hg atoms underpotentially deposited on Au(111) were resolved with the atomic force microscope. In sulfate, nitrate, and perchlorate electrolytes, a hexagonal overlayer with a 0.58 +/- 0.02-nm spacing was seen. In acetate, a hexagonal lattice exhibiting a 0.74 +/- 0.05-nm spacing was observed positive of the underpotential-deposition potential, a rhombic lattice with a 0.43 +/- 0.02-nm spacing was seen at intermediate potentials, and another hexagonal lattice with a 0.30 +/- 0.03-nm spacing was found just positive of bulk deposition.