CESyRa: A versatile setup for core-level absorption experiments on free metallic clusters using synchrotron radiation

The possibility to apply synchrotron radiation-based spectroscopic techniques, and in particular X-ray absorption spectroscopy (XAS), to isolated nanoparticles is expected to bring important insight into the electronic properties, the structural arrangement, and the chemical character of finite size systems. A precise knowledge of such properties has special relevance for a bottom-up approach to the description of nanostructured systems of technological interest. Element specificity, chemical sensitivity and local character are most significant qualities demanded from the characterization tools in this regards. The extremely low density of free particles samples is the main issue limiting the development of such techniques and only very recently first experimental results on systems of strong technological relevance like transition metal nanoparticles. In this paper we describe an experimental setup for core-level absorption investigations on free metal clusters. The most critical issues for experiment feasibility are discussed and the adopted methodology is described in detail. Results from the application of this approach to core-shell photo-ionization studies on free Ti clusters are presented as a case study.