Low-energy decay pathways of doubly charged silver clusters Ag_n²⁺ (n = 9 - 24)

The low-energy dissociation channels of mass selected silver cluster ions Ag_n²⁺ (n = 9 - 24) are determined by collision induced dissociation (CID) in a Penning trap. While all clusters of the size n ≥ 17 evaporate neutral monomers, most smaller clusters undergo asymmetric fission of the form Ag_n²⁺ → Ag_n-3⁺ + Ag₃⁺. However, Ag₁₅²⁺ and Ag₁₁²⁺ emit monomers which indicates shell or odd-even effects. The observed fragmentation pathways are different from previous reports of measurements with sputtered Ag_n²⁺.