Abstract
The cerium electronic configuration of very thin films deposited on Fe(100) has been studied by core level photoemission. In the low-coverage regime ( ⩽ 1 monolayer), cerium atoms are in a trivalent state (4f1 configuration). For larger coverages, cerium atoms exhibit a mixed valent state. This behaviour reflects the valence change of covered cerium atoms at the interface and results from the increase in the hybridization strength for these interface atoms. Owing to an original method, we were able to directly decompose our experimental spectra in two contributions corresponding to the covered ("bulk") and non-covered (surface) atoms.