Measurement of the B⁺and Al⁺intercombination and Sc¹²⁺forbidden transition rates at a heavy-ion storage ring

Abstract

Electric-dipole intercombination and forbidden transitions have been optically observed with ions circulating in a storage ring, and atomic lifetimes determined. For the 2s2p 3 P o 1 level in the Be-like ion B + , the measured lifetime of (97.65 ± 0.5) ms corresponds to a transition probability of (10.24 ± 0.05) s −1 . This result ties in with experimental work on the neighbouring ion C 2+ and with recent calculations. For the corresponding level 3s3p 3 P o 1 in the Mg-like ion Al + , a lifetime of (305±10) µs (transition rate (3280±100) s −1 ) has been measured, corroborating earlier experiments but not the more recent calculations. The transition probability of the M1/E2 transition between the fine-structure levels of the 2s 2 2p 5 2 P o ground state in F-like Sc 12+ has been determined as (1000 ± 30) s −1 , in agreement with the results of semi-empirically corrected multi-configuration Dirac-Fock calculations.

Tables of Atomic Transition Probabilities for Beryllium and Boron

“…Clearly, the agreement between the theoretical and experimental data is excellent, which is, however, not too surprising for these LS-allowed lines since they are among the strongest transitions in this spectrum. Also, for the very weak, LS-forbidden intercombination line, 2s 2 1 S-2s2p 3 P, a lifetime measurement performed with a storage ring 49 and another accurate theoretical result, 50 obtained with the advanced atomic structure code CIV 3, are available and are presented in Table 19, too. These results also show excellent agreement.…”

Optical frequency standards based on mercury and aluminum ions

“…3) was used for this demonstration. This transition has a natural linewidth of about 500 Hz, 36 so it is not the best choice for an optical frequency standard. More recently, the A B Figure 3.…”

Absolute transition probabilities of Al I and Al II spectral lines and intensity ratios within multiplets

“…In CI approximation the radiative lifetimes of a large number of excited levels of Al II were calculated (Chang & Fang 1995), namely 3sns (Trabert et al 1999) and in a ion trap experiment (Johnson et al 1986). The obtained data are in excellent agreement (within a 1% limit).…”