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Angle-scanned photoelectron diffraction measurements have been performed prior to and after CO exposure onto a Ni monolayer deposited on Pt(111). Ni is known to grow epitaxially on Pt(111), but there is evidence for an adsorbate-induced restructuring such that the initial atomically flat Ni layer gives place to at least two-layer-high Ni islands. As far as the driving force for the restructuring is concerned, some hypotheses can be put forward considering the Ni–Ni nearest neighbor distances in the Ni monolayer and in the restructured layer, along with some thermodynamical arguments.

The site (fcc or hcp) occupied by the atoms of a Ni ML deposited on Pt (111) is determined in this paper using angle-scanned photoelectron diffraction (PD). A full 2π MgK α-excited Ni-2p 3/2 PD pattern from 1-ML Ni deposited on Pt(111) is compared to single scattering cluster-spherical wave (SSC-SW) simulations and the agreement between experimental and theoretical data is quantified by R-factor analysis. From the present investigation it turns out that Ni atoms occupy hcp sites. In addition, the Ni-Pt distance has been estimated to be 2.5±0.1 Å.