Fragmentation of lead cluster ions (Pb N +: N = 2–20) in low-energy collisions with a highly oriented pyrolytic graphite surface has been investigated by means of a tandem time-of-flight mass spectrometer. At low incident energies, all clusters fragment dominantly by an atom loss process. This behavior is characteristic for clusters of metallic elements, but in contrast to Si N +, Ge N + and Sn N + clusters. The results therefore demonstrate differences in the electronic and geometric structure between lead clusters and the lighter group-14 element clusters. The low energy dissociation patterns were compared successfully with a recent theoretical study on lead cluster fragmentation, supporting the idea, that lead clusters cations already show signatures of metallic behavior unlike Si N +, Ge N + and Sn N + clusters of the same size.

A molecular beam apparatus has been developed for deposition and scattering experiments of size-selected clusters. The new setup combines a bimetallic laser ablation cluster source with a collinear time-of-flight mass spectrometer. Mass selection is achieved with a pulsed electrostatic mirror. A significantly improved transmission in combination with a reduction of the kinetic energy distribution of the mass selected clusters has been obtained. Without further modification of the apparatus, surface-induced dissociation of mass selected tin clusters has been investigated, demonstrating the possibility to combine cluster beam deposition and scattering experiments.