Experimental and Theoretical Radiative Parameters of Highly Excited Odd-parity Levels in Ir ii

Abstract

Using the time-resolved laser-induced fluorescence technique, the radiative lifetimes for 15 odd-parity levels from 47,003 to 61,475 cm−1 in Ir ii were measured. To the best of our knowledge, 11 lifetime results among these levels are reported for the first time, and hence they should be a good complement to the measured lifetime data of 10 levels previously published in the literature. The pseudorelativistic Hartree–Fock including core-polarization corrections method was used to calculate the lifetimes and branching fractions (BFs) of the investigated energy levels. Combining the experimental lifetime with the theoretical BFs, the transition probabilities and oscillator strengths for 124 transitions were determined.

On the sensitivity of uranium opacity with respect to the atomic properties in the context of kilonova emission modeling

“…Besides, since the cutoff radius is not an unambiguously defined parameter, Gamrath et al [45] determined that another definition of the core radius corresponding to a value 33% smaller only affects the computed radiative lifetimes by a few percents in the case of neutral lanthanum (La I). As previously observed in other weakly charged ions (e.g., [37,38]), CPOL effects reduce the f -values for both U II and U III by up to 10-15% in both cases. The direct consequence on the opacities can be observed when looking at Figs.…”

“…The latter can be approximately represented by a core polarization (CPOL) model potential, first introduced in HFR and described in details in [29]. It was shown that considering CPOL effects in HFR calculations can reduce the predicted oscillator strengths in some cases (e.g., [37,38]). The CPOL potential essentially depends on two parameters: the dipole polarizability of the ionic core, α d , and its cutoff radius, r c , often estimated as the outermost core orbital mean radius.…”