Beam-foil Studies of Phosphorus in the Vacuum Ultraviolet

Abstract

We have measured lifetimes for 24 terms in P I-P V using the beam-foil technique in the vacuum UV region. The results have been compared with theoretical calculations and with other experimental values. Several significant discrepancies with earlier results have been found. We present the first experimental lifetimes for 9 terms. Most of our lifetimes can be converted directly into f-values, and we discuss these in relation to trends along isoelectronic sequences. Configuration interaction is found to be important for several transitions. We also suggest a revision of the recently-determined abundance of phosphorus in interstellar clouds, based upon our new f-value for the 1 308 Å multiplet in P II.

Determination of polarizabilities and lifetimes for the Mg, Zn, Cd and Hg isoelectronic sequences

“…No uncertainties were quoted, but a propagation of quoted wavelength tolerances and an examination of variances in our own weighted least squares fit to these data indicated a minimum uncertainty of ±0.01a 3 0 . For the 3s3p 1 P o 1 level in P IV, two lifetime measurements using multiexponential curve fitting yielded conflicting results τ 3p = 0.22(2) [24] and 0.35(2) ns [25]. It can be seen from table 2 that the direct cascades from 3p 2 1 S 0 and 3s4s 1 S 0 are both theoretically predicted [19] to have a lifetime of 0.33 ns, very close to one of the measurements reported.…”

Oscillator strengths for ultraviolet transitions in P II and Cu II

“…The results of our lifetime measurements appear in Table 1 and the oscillator strengths derived from our branching fractions are given in Table 2. The tables also provide comparisons with earlier experimental (Livingston et al 1975;Smith 1978) and theoretical work (Hibbert 1988;Brage et al 1993;Tayal 2003;Froese Fischer et al 2006). The preferred f -values from Morton's most recent compilation (2003), which are based on the work of Livingston et al and Hibbert, are included in Table 2.…”

“…The above astronomical studies use oscillator strengths (f -values) compiled by Morton (1991Morton ( , 2003 from the theoretical computations of Hibbert (1988) and experimental lifetime of Livingston et al (1975). Hibbert's results represent an improvement over his earlier calculation (Hibbert 1986), which did not include the 3s 2 3p4p states.…”

Oscillator strengths for highly ionized atomic systems. Progress report, May 1, 1977--April 30, 1978. [Summaries of research activities at Pennsylvania State Univ]

“….f¥ t b) Weiss et al [22] c) Trefftz and Zare [23] d) Cowan and Widing [24] e) Weiss [25] f) Andersen et al [26] g) Anders en et al [27] h) Livingston et al [28] i) Berry et al [29] j) Livingston et al [30] k) Curtis et al [31] £) Livingston [7] .…”