ATOMIC DIFFUSION AND ELECTRONIC-STRUCTURES OF CE NI(110) AND CE/CU(110) SYSTEMS/

We have studied the electronic structures of Ce/Ni(110) and Ce/Cu(110) systems by measuring Ce 3d core-level X-ray photoelemission and Ce 4d -4f resonant photoemission. The distribution of the Ce atoms in the su rface layers was investigated by means of a medium-energy ion scatteri ng experiment. It was found that in Ce/Ni(110) Ce atoms occupy substit utional sites of the Ni substrate lattice after annealing. In the Ce/N i(110) system, the Ce 4f electronic structure depends on the content o f Ce atoms in the surface layers and shows considerable change by anne aling. In the Ce/Cu(110) system, the Ce 4f electronic structure is ins ensitive to the Ce concentration in the surface layers. The difference of Ce 4f electronic structures between two systems is discussed in co nnection with the difference of the hybridization strength of Ce 4f an d electronic states of the substrates.