ANGLE-RESOLVED PHOTOEMISSION-STUDY OF DY PD(111) AND CE/PD(111) SURFACE-COMPOUNDS/

Rare-earth (RE) palladium surface compounds have been studied by LEED and angle-resolved photoemission (ARPE). The compounds were prepared b y deposition of pure RE metals (Dy, Ce) on Pd(111) and subsequent anne aling. The films reveal a sharp (2 x 2) overstructure in the LEED patt erns that point to a surface geometry equivalent to REPd3(111). The AR PE data are in good agreement with LCAO band-structure calculations fo r this compound. Particularly, an experimentally observed shift of the Pd ld-derived bands to higher binding energies in going from the Dy- to the Ce-based compound is convincingly reflected in the calculations and attributed to the influence of a non-integer occupancy of the Ce 4f states.