Mass Spectrometric Study of Ions Formed from Cesium Metaborate Vapor under Electron Impact

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An ionization behavior of cesium metaborate vapor under electron impact has been studied by a mass spectrometric method. Formations of Cs²⁺, CsB⁺, CsO⁺, Cs₂⁺, Cs₂O⁺, B⁺ and BO₂^- ions have been identified in addition to the well known ions of Cs⁺, CsBO⁺, CsBO₂⁺ and Cs₂BO₂⁺. Ionization processes and vapor precursors for these ions have been given from ionization efficiency curves, appearance energies, temperature dependence of ion intensities and energetics of the ionization processes as follows: the process for the formations of Cs⁺ with AE(Cs⁺)=3.9±1.0 eV and BO₂^- ions is the ion pair formation from CsBO₂(g), that for CsBO₂⁺ ion is the simple ionization of CsBO₂(g), that for Cs⁺ with AE(Cs⁺)=9.1±0.5 eV, Cs²⁺, CsBO⁺, CsB⁺, CsO⁺ and B⁺ ions is the dissociative ionization from CsBO₂(g) and that for Cs₂⁺, Cs₂O⁺ and Cs₂BO₂⁺ ions is the dissociative ionization from Cs₂(BO₂)₂(g). The know-ledge of the ionization behavior of cesium metaborate vapor under electron impact is very useful in the mass spectrometric study of vaporization behaviors of CsBO₂(s) and simulated radioactive waste borosilicate glasses.