Multiconfiguration calculations of electronic isotope shift factors in Al i

Abstract

The present work reports results from systematic multiconfiguration Dirac-Hartree-Fock calculations of electronic isotope shift factors for a set of transitions between low-lying levels of neutral aluminium. These electronic quantities together with observed isotope shifts between different pairs of isotopes provide the changes in mean-square charge radii of the atomic nuclei. Two computational approaches are adopted for the estimation of the mass-and field-shift factors. Within these approaches, different models for electron correlation are explored in a systematic way to determine a reliable computational strategy and to estimate theoretical error bars of the isotope shift factors.

Theoretical study of the hyperfine-interaction constants and the isotope-shift factors for the 3s21S0–3s3pZhang1, Xie2, Li3 et al. 2017Phys. Rev. A

“…the "MR-SD" model. It was shown that this method is capable of accounting for the electron correlation for the complex ions and atoms [32,[39][40][41][42][43].…”

Multiconfiguration calculations of electronic isotope-shift factors in Zn i

“…It is important to mention that core-core (CC) contributions, i.e., unrestricted SD substitutions from core orbitals, are not accounted for, contrary to the strategy adopted in the papers on Mg I [37] and Al I [38]. Indeed, the CSF expansions in Zn I become too large when CC correlations within the complete 2s 2 2p 6 3s 2 3p 6 3d 10 core orbitals are added to the nl = 9h AS, counting for the J π = 2 − state more than 10 8 CSFs for the SrD-MR and SrDT-SS models.…”

“…[37,38,52]. Hence, neglecting CC contributions enables us to use separate orbital basis sets, in which orbital relaxation is allowed.…”

“…Later on, it has been applied to neutral magnesium (Mg I) [37] and neutral aluminum (Al I) [38], where IS factors have been computed for transitions between low-lying states. In the present work, different electron correlation models are applied to Zn I to estimate theoretical error bars of the IS factors.…”

Isotope shifts from collinear laser spectroscopy of doubly charged yttrium isotopes

“…This approach of an active space expansion using a multireference has been previously described in Refs. [36,37]. Based on this reference set, single and double excitations from the 4p, 4d, 5s, and 5p orbitals to correlation orbitals nl with l g were considered.…”