In-Plane Structure of Underpotentially Deposited Copper on Gold (111) Determined by Surface EXAFS (Extended X-Ray Absorption Fine Structure).
Interim technical rept.,
PUERTO RICO UNIV RIO PIEDRAS DEPT OF PHYSICS
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The Surface Extended X Ray Absorption Fine Structure SEFAFS spectrum of an electrochemically deposited ad-layer of copper on a gold 111 electrode immersed in solution and under potential control was obtained by employing fluorescence detection and grazing incidence geometry. The x-rays were polarized parallel to the plane of the gold surface. Two peaks were observed in the radial distribution function, indicating two different near neighbors for copper. The near neighbors were determined to be gold at 2.58 plus or minus 0.03 angstrom and copper at 2.92 plus or minus 0.03 angstroms. The copper-copper distance is identical to the gold-gold lattice spacing showing that at full coverage, the copper ad-layer forms at 1 x 1 commensurate layer on the gold 111 substrate. The intensity of the gold-copper scattering relative to the copper-copper suggests the copper atoms sit in 3 fold hollows sites.
- Inorganic Chemistry
- Physical Chemistry