Many body study of the Bohr-Weisskopf effect in the thallium atom

TL;DR

This study uses relativistic coupled cluster calculations to analyze hyperfine structures and the Bohr-Weisskopf effect in thallium isotopes, achieving high accuracy and predicting nuclear magnetic moments.

Contribution

It demonstrates the effectiveness of Gaussian basis sets in relativistic calculations and provides new insights into the Bohr-Weisskopf effect in thallium isotopes.

Findings

Hyperfine structure constant uncertainty < 1% for Tl ground state

Significant 16% Bohr-Weisskopf correction for 6P3/2 state

Predicted nuclear magnetic moments for short-lived Tl isotopes

Abstract

We report the relativistic coupled cluster study of the hyperfine structure and effect of the nuclear magnetization distribution (Bohr-Weisskopf effect) in the $6P_{1/2}$, $6P_{3/2}$ and $7S_{1/2}$ states of several Tl isotopes. It is shown that the Gaussian basis set can be used in such electronic structure calculations and provide a good accuracy. For the ground electronic state of the neutral Tl atom achieved uncertainty for the hyperfine structure constant is smaller than 1\%. A strong Bohr-Weisskopf correction (about 16\%) was found for the $6P_{3/2}$ state which can be of interest for the nuclear structure theory. Basing on the theoretical treatment as well as the available experimental data nuclear magnetic moments of short lived ${}^{191}$Tl and ${}^{193}$Tl isotopes were also predicted.