Observation of new set of anomalies in mass spectra of CsI cluster ions close to the ionization threshold

Abstract

(CsI${)}_{\mathrm{n}}$ clusters are generated by inert-gas condensation and analyzed by time-of-flight mass spectrometry. The stability of cube-shaped nonstoichiometric (${\mathrm{Cs}}_{\mathrm{n}}$ ${\mathrm{I}}_{\mathrm{n}\mathrm{-}1}$ ${)}^{\mathrm{t}}$, ions as observed before in secondary-ion mass spectrometry, is confirmed for n=14 and 23 at ionization energies beyond 15 eV. With lowered electron energy, the spectra show enhanced intensities for n=7, 10, 13, 17, 19, and 25 that arise neither from neutral nor from charged compact cube-shaped CsI clusters.