Adsorption of xenon on Ni(111) studied by photoemission and LEED

Abstract Adsorption of xenon on Ni(111) has been studied by LEED and by partly integrated photoemission UPS Hel at a polar angle of detection from 0° to 30°. An incommensurate structure has been evidenced at monolayer completion. For xenon coverages slightly lower than one monolayer complex LEED patterns have been obtained. They have been interpreted in terms of coexisting Xe p(2 × 2) domains and Xe hexagonal domains. Xe5p 1 2 and Xe 5p 3 2 splitting into two components has been observed in both first and second monolayers when the photoelectrons are detected along the normal to the surface. Adsorption on two different types of sites and indirect transition processes have been considered to interpret this splitting. The angular behaviour of the photoelectron spectra strongly supports the latter interpretation. A xenon bandwidth of 0.3 eV has been deduced. This value is fully consistent with the XeXe distance of 0.44 nm deduced from LEED for the incommensurate structure.