Dissociation channels of silver bromide cluster Ag₂Br, silver cluster Ag₃ and their ions studied by using alkali metal target

Abstract.

Various dissociation channels of silver bromide cluster ion Ag₂Br⁺ and silver cluster ion Ag₃ ⁺ were observed in high-energy collisionally-activated dissociation (CAD) using a Cs target. The fragment patterns of the high-energy CAD were compared with those of the metastable dissociation and low-energy CAD. The difference in the fragment patterns between the high-energy CAD and the other dissociation methods was explained in terms of the internal energy distributions. The dissociation mechanisms of neutral silver bromide cluster Ag₂Br and silver cluster Ag₃ were also investigated by charge inversion mass spectrometry using the Cs target. While the fragment ions AgBr^- and Ag₂ ^- were dominantly observed in the charge inversion spectrum of Ag₂Br⁺, the undissociated ion Ag₃ ^- was observed as a predominant peak in the case of Ag₃ ⁺. The dissociation behavior of Ag₂Br^* can be explained on the basis of the calculated thermochemical data. Contrary to this, the predominant existence of the undissociated Ag₃ ^- cannot be explained by the reported thermochemical data. The existence of undissociated Ag₃ ^- suggests that the dissociation barrier is higher than the internal energy of Ag₃ ^* (theoretical: 1.03 eV, experimental: 2.31 eV) estimated from the ionization potentials of Ag₃ and Cs.