Three-body fragmentation dynamics of BrCN^q+ (q=3-6) induced by 1-keV electron impact

The three-body fragmentation dynamics of BrCNq+ (q = 3-6) produced by 1-keV electron impact has been investigated using the ion momentum imaging technique. Up to 11 three-body Coulomb explosion channels were identified and analyzed. The corresponding kinetic energy release (KER) distributions were obtained and compared with the predictions of the Coulomb explosion model. By means of the Dalitz plot, Newton diagram, and native frame method, we have studied the concerted and sequential fragmentation mechanisms for channels leading to Brl+ + C+ + N+ (l = 1-3). The KER for the intermediate dications BrC2+ and CN2+ from the sequential mechanism were determined and the electronic states of the intermediate molecular ion CN2+ were discussed. For the channels leading to higher charge states of the carbon and nitrogen ions, only the concerted fragmentation mechanism was observed.