Energy levels and radiative rates for transitions in Cr-like Kr XIII, Tc XX and Xe XXXI

Discrepancies in Atomic Data and Suggestions for Their Resolutions

“…For the 3s3p 2 4 P 1/2,3/2,5/2 levels of Si II, Calamai et al [35] have measured τ which are lower than our theoretical results [34] by an order of magnitude. The dominant contributing E1 transitions for these levels are invariably weak as their f-values are ∼10 −7 , and hence large variations among different calculations are not uncommon as discussed above and also seen in table 3 and fig. 3 of [36].…”

“…For many ions 'configuration interaction' (CI) among a few hundred levels (or configuration state functions, i.e. CSF) is sufficient to generate reasonably accurate energies (within a few percents), but for some much larger calculations (∼10 9 or more CSFs) are necessary, such as for Cr-like ions [3,4,5].…”

“…Availability of measurements for some levels, as stated above, considerably helps in determining the theoretical energies and/or in improving the calculations, because various methodologies (such as optimising orbitals on particular state/level or the use of non-orthogonal or pseudo orbitals) can be applied. However, the problem becomes more difficult when no measurements (and even prior theoretical results) are available for comparisons, as recently experienced for three Cr-like ions: Kr XIII, Tc XX and Xe XXXI [3]. For many ions 'configuration interaction' (CI) among a few hundred levels (or configuration state functions, i.e.…”

“…For many ions 'configuration interaction' (CI) among a few hundred levels (or configuration state functions, i.e. CSF) is sufficient to generate reasonably accurate energies (within a few percents), but for some much larger calculations (∼10 9 or more CSFs) are necessary, such as for Cr-like ions [3,4,5].Usually, discrepancies between theory and measurements (or among various calculations) are understandable, and can be resolved by different methodologies as stated above. For example, Turkington et al [6] reported two sets of theoretical energies for the levels of Na-like W LXIV, for which they used two different atomic structure codes, namely CIV3 and GRASP.…”

Radiative rates for E1, E2, M1, and M2 transitions in F-like ions with55≤Z≤73

“…Comparison of results with existing data are always useful and considerably help in improving the calculations -see for example the recent work of Guo et al [22] on W XL and the references within the paper. However, the problem arises when no prior data exist as noted for some of the Cr-like ions [23]. Similarly, if measurements are available, even for a few levels, it considerably helps to improve the calculations, as was the case for some other Cr-like ions -see Table A of [24].…”