Multiply charged atomic and molecular ions from laser multiphoton ionisation of UF6

✍ Scribed by M. Stuke; C. Wittig

• Publisher: Elsevier Science
• Year: 1981
• Tongue: English
• Weight: 187 KB
• Volume: 81
• Category: Article
• ISSN: 0009-2614
• DOI: 10.1016/0009-2614(81)85351-1

✦ Synopsis

Multiply charged atomic and molecular ions are detected following laser multiphoton ionisation of UF, vapor under collision-free conditions. Most multiply charged molecular ions are thermodynamically unstable with respect to dissociation into singly charged fragment ions [l-3] _ They are therefore hard to prepare, detect, and identify, and as a consequence there is very littie information available concerning the physical and chemical properties of such species. Present means of preparing multiply charged species do-not yield densities which are sufficiently high for even very sensitive spectroscopic methods (e.g. LIF) td be exploited, and molecular ions with lifetimes shorter than *lCV6 s often go undetected for lack of adequate time resolution. In this brief communication, we report the observation of multiply charged atomic and molecular ions following laser multiphoton ionisation (MPI) [4--81 of UFg vapor under collision-free conditions_ We believe this to be the first report of multiply charged species following MPI, but more importantly we believe that the phenomenon can be rather general, and can be exploited in several areas of applied science. The experimental arrangement consists of a main vacuum chamber, a separately pumped quadrupole mass spectrometer (UT1 IOOC) whose modified ion source region extends into the center of the main vacuum chamber, the 266 run fourth harmonic of a * Research supported by the USC Joint Services Electronics Program.