Atomic calculations of hyperfine structure anomaly in gold

TL;DR

This paper calculates hyperfine structure constants in gold and gold-like mercury, accounting for the Bohr-Weisskopf effect, to better understand nuclear properties and improve extraction of BW corrections from experimental data.

Contribution

It introduces atomic factors for hyperfine calculations in gold, enabling extraction of BW corrections for unstable nuclei, and assesses the validity of the single-particle model in describing experimental data.

Findings

Atomic factors enable BW correction extraction from experimental data.

Single-particle model describes some gold isotopes well, but not all.

Configuration mixing effects are significant in certain gold isotopes.

Abstract

The magnetic hyperfine structure constants have been calculated for low-lying levels in neutral gold atom and gold-like ion of mercury taking into account Bohr--Weisskopf (BW) effect. BW effect is represented as a product of atomic and nuclear ($d_\mathrm{nuc}$) factors. We have calculated the atomic factors, which enable one to extract BW-correction values for far from stability gold nuclei from the experimental data. The possible uncertainty of our atomic calculations have been estimated by the comparison with the available experimental data. It has been shown that the standard single-particle approach in $d_\mathrm{nuc}$ calculation reasonably well describes experimental data for $11/2^-$ gold isomers and $3/2^+$ ground state of $\rm ^{199}Au$. At the same time, it fails to describe the hyperfine constant in $^{197}\mathrm{Au}$. This indicates the more pronounced configuration mixing in $\rm ^{197}Au$ than in $\rm ^{199}Au$.