Beam-foil lifetime study of neon-like Ti12+

Critical Assessment of Theoretical Calculations of Atomic Structure and Transition Probabilities: An Experimenter’s View

“…The process was assisted by beam-foil lifetime work at Bochum, comparing results on the 2s 2 2p 5 3p and 2s 2 2p 5 3d level lifetimes mostly to Fawcett's tabulations, and by Cowan code computations at Lund. As an example, most of the 2s 2 2p 5 3p levels in Ti XIII have a lifetime on the order of 200 ps, while most of the 2s 2 2p 5 3d levels in the same system feature lifetimes on the order of 100 ps, experiment on Ti (and correspondingly on S) [172,173] agreeing with the computations.…”

Relativistic many-body calculations of electric-dipole lifetimes, transition rates and oscillator strengths for 2l−13l′ states in Ne-like ions

“…Experimental studies of lifetimes of the n = 3 states have been made using the beam foil techniques. Most of these investigations were focused on low-Z ions: Si 4+ [57], P 5+ [57], S 6+ [57][58][59][60][61][62], Cl 7+ [58,[62][63][64], Ar 8+ [60,63,65], Ti 12+ [66], Cr 14+ and Fe 16+ [67]. Lifetime measurements for the high-Z ion, Cs 45+ , [68] have also been reported.…”

EUV Beam-Foil Spectra of Titanium, Iron, Nickel, and Copper

“…Intercombination transitions (with a change of spin, thus connecting term systems of different multiplicity) have lower transition rates and consequently longer upper level lifetimes, by about two orders of magnitude [86,87] or more. For the E1-allowed decays, a typical upper level lifetime for ions of charge states as discussed so far would be expected in the range of 10 to 200 ps [76,78], whereas the upper level lifetimes of 3s-3p intercombination transitions would be expected in the range of 20 to 1000 ns. The former decays are visible as emission from the ion beam close to the exciter foil (the first few mm), whereas the latter are much weaker per section of the ion beam, but they survive out to distances of many cm from the foil.…”

“…An atomic structure problem closely related to the two-electron systems is the one-electron-one-vacancy system of singly excited Ne-like ions. For Ti, this is the spectrum Ti XIII, on which Bochum beam-foil work extensively investigated the level structure [76,77] and level lifetimes [78]. At the same time, the Lund group of Litzén and Jupén was involved in studies of laser-produced plasmas of iron-group elements [79], resulting in some parallel analyses (largely agreeing in the level structure and wavelength results with Bochum and Lyon beam-foil work) and several collaborative studies (among others, see [52,53,[80][81][82][83]).…”

“…At the same time, the Lund group of Litzén and Jupén was involved in studies of laser-produced plasmas of iron-group elements [79], resulting in some parallel analyses (largely agreeing in the level structure and wavelength results with Bochum and Lyon beam-foil work) and several collaborative studies (among others, see [52,53,[80][81][82][83]). A success of the beam-foil technique is the identification of the Ti XIII 2s 2 2p 5 3p 3 S 1 level decay (to the 2p 5 3s 3 P o 2 level) by a combination of spectroscopy and lifetime measurements [78]. Interestingly, in the same configuration, the 2s 2 2p 5 3p 1 S 0 level position and decay (two decay channels) are still disputed because candidates for one or both of the two lines are blended in most iron group elements, and the computed level lifetime does not significantly differ from those of many other levels, hence the experiment could not test this parameter for discrimination.…”