Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
9746659 | International Journal of Mass Spectrometry | 2005 | 5 Pages |
Abstract
Lifetimes of the IrBr62â and IrCl62â gas-phase ions were measured in an electrostatic ion storage ring as 3.3 ± 0.1 s and 3.1 ± 0.1 s, respectively. The lifetimes indicate that the dianions are not subject to spontaneous decay under ambient conditions, since they are associated with decay resulting solely from high-energy collisions with residual gas (â¼5 Ã 10â11 Torr) that is present in the ring. To further investigate the high-energy collisional decay dynamics, IrBr62â and IrCl62â were subjected to high-energy collision induced dissociation measurements in an accelerator mass spectrometer (ion translational energy in laboratory frame = 100 keV). A number of daughter ions were formed following the high-energy collisions (e.g., IrCl62â produced IrCl6â, IrCl5â, IrCl4â, IrCl3â and Clâ). The presence of the intact monoanion (i.e., IrCl6â) indicates that electron detachment is a prominent decay process, in contrast to low-energy collisional excitation where IrCl5â and Clâ are produced via ionic fragmentation. The predominance of electron detachment occurring as a result of high-energy collisions was further illustrated by charge-reversal measurements where cationic daughter fragments were observed, consistent with triple electron detachment. This measurement indicates that high-energy collisional activation of dianions should represent a general approach for studying triple electron detachment of molecular anions.
Keywords
Related Topics
Physical Sciences and Engineering
Chemistry
Analytical Chemistry
Authors
William E. Boxford, Mohamed O.A. El Ghazaly, Caroline E.H. Dessent, Steen Brøndsted Nielsen,