Argon coated alkali halide clusters: the effect of the coating on the ionization and fragmentation dynamics

We present an investigation of the formation, ionization and fragmentation processes of a new class of clusters consisting of an ionically bound clust er core, coated by a shell of Van der Waals bound atoms. Element specific s oft X-ray photoionization spectroscopy was used to investigate the alkali h alide cluster core and the Ar coating separately. The thickness of the coat ing controls the mechanism of ionization and fragmentation of these inhomog eneous clusters. Unusual metastable structures of alkali halide clusters we re observed when the thickness of the coating exceeded two monolayers. (C) 2000 Elsevier Science B.V. All rights reserved.