Sputtered metal and silicon cluster ions: collision-induced fragmentation and neutralization

Mass separated metal and silicon cluster ion beams M _n ^{+, ?} are produced by sputtering and undergo fragmenting and/or neutralizing collisions at different kinetic energies (100–1800 eV) in Ar and SF₆. Fragment patterns induced by rare gas collisions open a way to determine ionization potentials and electron affinities of clusters. These values are compared to known experimental and theoretical data. For negatively charged clusters the absorption in gas targets is mainly due to neutralization, the cross sections varying with cluster material, number of atoms and collision partner from 10 Ų to about 50 Ų.