SUPERSTRUCTURES OF PB MONOLAYERS ELECTROCHEMICALLY DEPOSITED ON AG(111) - COMMENT

Using scanning tunneling microscopy, a long-wavelength pattern was obs erved by Muller et al. [Phys. Rev. B 46, 12 899 (1992)] in Pb monolaye rs on Ag(111) formed by underpotential electrochemical deposition. We point out that the monolayer is incommensurate and so it should be des cribed as having substrate-induced spatial modulations, and we also de monstrate that one can accurately calculate the long-wavelength spacin g and rotation angle, which are shown to depend on electrode potential .