Auger parameter of small Pd clusters in a zeolite matrix: experimental investigation and application of a simple electrostatic model

In this communication the relationship between the Pd Auger parameter shifts and the nuclearity of Pd clusters entrapped in Y zeolites is investigated. It is shown that a simple electrostatic model is useful to estimate this dependence. It is demonstrated that the Auger parameter shift depends not only on the nuclearity and geometry of the cluster but also on the nature of the heteroatoms in its close vicinity. This result could be explained by the influence of these heteroatoms on the electronic polarisability of the surface Pd atoms of the cluster.