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

摘要

Various dissociation channels of silver bromide cluster ion Ag2Br+ and silver cluster ion Ag+ 3 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 Ag 2 were dominantly observed in the charge inversion spectrum of Ag2Br+, the undissociated ion Ag 3 was observed as a predominant peak in the case of Ag+ 3 . 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 Ag 3 cannot be explained by the reported thermochemical data. The existence of undissociated Ag 3 suggests that the dissociation barrier is higher than the internal energy of Ag 3 (theoretical: 1.03 eV, experimental: 2.31 eV) estimated from the ionization potentials of Ag3 and Cs.