X-ray photoelectron spectroscopy of low surface concentration mass-selected Ag clusters

We have developed an experimental setup for the study of small mass-selecte d clusters delivered by soft landing to a model oxide support. An automated deposition system to achieve accurately quantified homogeneous surfaces is described which also overcomes beam instability. Finally we present some r ecent photoelectron spectroscopic data from the analysis of mass-selected A g-n(+) clusters deposited on a Xe covered Al2O3 surface. Large core-level b inding energy shifts are observed as a function of deposited cluster size a nd diffusion/agglomeration within the noble gas layer. (C) 2000 American In stitute of Physics. [S0021-9606(00)70544-7].