Positively and Negatively Charged Cesium and (C) Cs Cluster Ions.

We report on the formation and ionization of cesium and CCs clusters in superfluid helium nanodroplets. Size distributions of positively and negatively charged (C) Cs ions have been measured for ≤ 7, ≤ 12. Reproducible intensity anomalies are observed in high-resolution mass spectra. For both charge states, (C) Cs and (C) Cs are particularly abundant, with little dependence on the value of . Distributions of bare cesium cluster ions also indicate enhanced stability of Cs and Cs, in agreement with theoretical predictions. These findings contrast with earlier reports on highly Cs-doped cationic fullerene aggregates which showed enhanced stability of CCs building blocks attributed to charge transfer. The dependence of the (C) Cs anion yield on electron energy shows a resonance that, surprisingly, oscillates in strength as increases from 1 to 6.