LIFETIMES OF METASTABLE LEVELS OF ATOMIC IONS

For the last two decades, lifetimes of metastable levels with times ranging from hundreds of microseconds to many seconds have been measured on ions with low charge stored in Paul, Penning, and Kingdon ion traps. Recent developments in the capture of external ions into traps, use of the Electron Beam Ion Trap, and the employment of heavy ion storage rings now have greatly extended the range of charge states of stored ions which can be studied. There is also a continued demand for lifetime measurements on ions with low charge states, as tests for the development of many-electron theories and driven by astrophysical needs. Transition rates for intersystem lines of C+, precise lifetime measurements on the 2 S-3(1) level of helium-like C4+, N5+, and Ne8+, lifetimes of levels of several charge states of argon to Ar10+, and a measurement of a hyperfine structure level lifetime on hydrogenlike Bi-209(82+), all completed during the last two years, illustrate these current trends.