Coverage-dependent diffuse spin-polarized electron diffraction analysis of CO on Pt( [formula omitted

Abstract

The coverage dependence of the local adsorption structure of carbon monoxide on Pt(1 1 1) is investigated by means of diffuse spin-polarized electron diffraction (DSPLEED). We present the theoretical discussion of the scattering of spin-polarized electrons from the disordered CO layer adsorbed on the Pt(1 1 1) surface. The spin-dependent diffuse low-energy electron diffraction (LEED) intensity and the resulting diffuse scattering asymmetry parameter are calculated for different adsorption structures of CO connected with different coverages. We report the energy as well as the angular dependence of the diffuse relativistic intensity and of the spin–orbit asymmetry. We explore the information that may be extracted from the DSPLEED rotation curves which are calculated at a selected beam energy. The polar angle of incidence of a polarized beam is held fixed and the azimuthal angle is scanned. We are focusing on the sensitivity of features in the rotation curves to the coverage-dependent structure of the adlayer keeping other geometrical parameters of the CO/Pt(1 1 1) system fixed. We find the rotation curves to be very sensitive with respect to the correlation effects governing the adlayer formation while the energy-dependent DSPLEED spectra do not expose such strong dependency.