STRUCTURAL INVESTIGATIONS ON XE PD(111) WITH SPIN-POLARIZED LEED/

(Square-root 3 x square-root 3)R30-degrees-Xe/Pd(111) and the dilute p hase of Xe/Pd(111) were investigated with spin-polarized low-energy el ectron diffraction (SPLEED). In the experiment spin-polarized electron s from a GaAs source were scattered and the spin-dependent intensities were measured. Comparative calculations were carried out by means of a relativistic LEED program. The structure determination of (square-ro ot 3 x square-root 3)R30-degrees-Xe/Pd(111) yields a layer distance of 3.5 +/- 0.1 angstrom, the Xe atoms being adsorbed in hollow sites. In the dilute phase of Xe/Pd(111) the adsorbed Xe atoms occupy on-top si tes with a Xe-Pd distance of 4.0 +/- 0.1 angstrom without two-dimensio nal periodicity.