Surface-induced fragmentation of tin cluster ions on a highly oriented pyrolytic graphite surface

Fragmentation and ion-scattering processes in the low-energy (0∼200 eV) collisions of Snx+ (x=8∼13) with a highly oriented pyrolytic graphite (HOPG) surface have been investigated by a tandem time-of-flight mass spectrometer. The fragmentation patterns in the lowest energy spectra changed drastically between Sn11+ and Sn12+:Sn6+ and Sn7+ fragments were predominantly observed for the Sn12+ and Sn13+ incidences, while fragments such as Snx−1+,Snx−2+,… were observed for Snx+(x=8∼11). Such characteristics are very similar to those reported in the dissociation studies of silicon and germanium cluster ions, and thus support the structural similarities among Si, Ge and Sn clusters.