4f-surface binding energy shift for Eu and Gd metals

Abstract Synchrotron radiation excited photoemission spectra of Eu and Gd are presented. For Eu a 4 f -surface component is resolved with 0.63 eV binding energy shift. For Gd the comparison with XPS data gives strong evidence for a surface shifted 4 f -component ( ΔE =0.48 eV). The mean free path of photoelectrons is determined.