Electronic configuration of Ce in Ce/Fe(100) and Ce/Pd(100)

The electronic state of cerium has been investigated by photoemission spect roscopy in ultra thin films of cerium deposited on monocrystalline Fe and P d. In both systems, we demonstrated the reduced Ce configuration admixture in the surface layer. We were also able to obtain core level spectra withou t any surface contribution. In the Ce/Pd system, the "bulk" spectra clearly show an exceptional configuration mixture suggesting that Co is in the int ermediate valence regime. (C) 1999 Elsevier Science B.V. All rights reserve d.