Eur. Phys. J. D 45, 279-287 (2007)
https://doi.org/10.1140/epjd/e2007-00265-7

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

¹ Division of Sustainable Energy and Environmental Engineering, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, 565-0871, Osaka, Japan
² Department of Chemistry, Graduate School of Science, Osaka Prefecture University, 1-1 Gakuencho, Nakaku, Sakai, 599-8531, Osaka, Japan
³ Department of Physics, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, 560-0043, Osaka, Japan

Corresponding author: ^a hayakawa@c.s.osakafu-u.ac.jp

Received: 28 June 2007
Revised: 14 August 2007
Published online: 19 September 2007

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.