Surface EXAFS analysis of crystallographic and dynamical properties of a layer of cobalt adsorbed on (111) and (110) faces of copper

Some crystallographic and dynamical surface properties are studied in this surface EXAFS investigation of monolayer and submonolayer amounts of cobalt deposited on copper (111) and (110). The authors show that two-dimensional islands are the first stages of cobalt adsorption and they measure a contraction of the first interlayer distance which is about 4% for the (111) face and 11% for the (110) face. Temperature- and polarisation-dependent amplitude measurements also provide evidence for the enhancement of perpendicular vibration amplitudes of surface atoms, the magnitude of which agrees with a rough estimation of the measured mean-square relative displacement. For the (110) face they show a reduction of these displacements which they relate to the strong contraction of the interlayer spacing and thus to the stiffening of the interatomic surface force constant.