Radiative rates for E1, E2, M1, and M2 transitions in Ne-like Hf LXIII, Ta LXIV and Re LXVI

Abstract

Calculations for energy levels, radiative rates and lifetimes have been performed for three Ne-like ions, namely Hf LXIII, Ta LXIV and Re LXVI, for which the general-purpose relativistic atomic structure package (GRASP) has been adopted. Results are presented among the lowest 121 levels of these ions, which belong to the 2s 2 2p 6 , 2s 2 2p 5 3ℓ, 2s2p 6 3ℓ, 2s 2 2p 5 4ℓ, 2s2p 6 4ℓ, and 2s 2 2p 5 5ℓ configurations, but CI (configuration interaction) has been considered among a much larger number of levels. No measurements for energy levels are available but comparisons have been made with the earlier similar theoretical results. Additionally, calculations have also been performed with the flexible atomic code (FAC) in order to assess the effect of (much) larger CI on energy levels.

Energy Levels and Radiative Rates for Transitions in F-like Sc XIII and Ne-like Sc XII and Y XXX

“…In addition, for a few levels, such as 79-84, there are some (minor) differences in energy orderings, but overall there are no (major) discrepancies between calculations with two different codes. This result was expected and has been noted earlier for several ions, including some Ne-like [14,15], although some authors, such as [21], have shown differences of up to ∼2 Ryd, but their calculations are incorrect as discussed in [14,15] and further explained in [22,23] -see also [24] for many other examples of discrepancies. Although a good agreement between the two calculations in our work confirms the accuracy of the calculated energies, we discuss these further below.…”

“…Similarly, with FAC, we have performed mainly three sets of calculations, which are: (i) FAC1, which includes 3948 levels of the same configurations as in GRASP, (ii) FAC2, which includes 17 729 levels arising from all possible combinations of 2*8, (2*7) 3*1, 4*1, 5*1, 6*1, 7*1, (2*6) 3*2, 3*1 4*1, 3*1 5*1, 3*1 6*1, and 3*1 7*1, and finally (iii) FAC3, which includes a total of 93,437 levels, the additional ones arising from (2*6) 4*1 5*1, 4*1 6*1, 4*1 7*1, 5*1 6*1, 5*1 7*1, 6*1 7*1, and 2*5 3*3. These calculations are on the same lines as considered for some other Ne-like ions [14,15].…”

“…Our final calculations with grasp include 3948 levels from 64 configurations, namely 2s 2 2p 6 , 2s 2 2p 5 3ℓ, 2s2p 6 3ℓ, 2s 2 2p 5 4ℓ, 2s2p 6 4ℓ, 2s 2 2p 5 5ℓ, 2s2p 6 5ℓ, 2s 2 2p 5 6s/p/d, 2s 2 2p 5 7s/p/d, (2s 2 2p 4 ) 3s3p, 3s3d, 3p3d, 3s 2 , 3p 2 , 3d 2 , 3s4ℓ, 3s5ℓ, 3p4ℓ, 3p5ℓ, 3d4ℓ, and 3d5ℓ. Similarly, with fac we have performed mainly three sets of calculations, which are: (i) FAC1, which includes 3948 levels of the same configurations as in GRASP, (ii) FAC2, which includes 17 calculations are on the same lines as considered for some other Ne-like ions [14,15].…”

“…However, such comparisons are very limited and hence cannot be confidently relied upon. In conclusion, on the basis of the (whatever possible) comparisons have been made for all three ions, our experience on a wide range of other ions, including F-like [4,13] and Ne-like [14,15], and considering that we have included a large CI as well as relativistic effects in generating wavefunctions, we assess the accuracy of our radiative rates to be about 20%, for a majority of strong transitions with f ≥ 0.1. …”

“…As in our earlier work on several F-like [4,13] and Ne-like [14,15] ions, we adopt the fully relativistic GRASP (general-purpose relativistic atomic structure package) code of Grant et al [16] to determine the atomic structure, and subsequently to calculate energy levels and A-values. However, this earlier version has been significantly revised by Dr. P.H.…”