X-RAY SURFACE DIFFRACTION OF METAL DEPOSITS AT METAL LIQUID INTERFACES - PART I - COPPER-DEPOSIT ON AU(100)/

In this work the Cu deposition on Au(100) in aqueous perchloric acid h as been investigated by in situ X-ray surface diffraction (XRSD). The Cu deposition reaction on gold single crystals exhibits an underpotent ial deposition (UPD) whereby a fraction of a monolayer is formed. The XRSD measurements show that the Cu UPD layer has a primitive (1 x 1) s tructure and that the adsorbed Cu species sit in fourfold hollow sites with a vertical distance between the Cu adlayer and the gold surface of 1.4 Angstrom. The results are discussed in consideration of STM,(1) EXAFS(2) and XSW3 experiments.