Relativistic Fock space coupled cluster study of bismuth electronic structure to extract the Bi nuclear quadrupole moment

TL;DR

This paper uses advanced relativistic electronic structure calculations to accurately determine the nuclear quadrupole moment of bismuth-209, improving the understanding of its nuclear properties.

Contribution

It introduces a relativistic Fock space coupled cluster approach for precise extraction of nuclear quadrupole moments from atomic data.

Findings

Quadrupole moment of $^{209}$Bi is determined as -418(6) mb.

The calculated quadrupole moment agrees with molecular data.

Atomic calculations enable correction of quadrupole moments for unstable Bi isotopes.

Abstract

We report the value of the electric quadrupole moment of $^{209}$Bi extracted from the atomic data. For this, we performed electronic structure calculations for the ground $^4S^o_{3/2}$ and excited $^2P^o_{3/2}$ states of atomic Bi using the Dirac-Coulomb-Breit Hamiltonian and the Fock space coupled cluster method with single, double, and full triple amplitudes for the three-particle Fock space sector. The value of the quadrupole moment of $^{209}$Bi, $Q(^{209}$Bi$)=-418(6)$~mb, derived from the resulting electric field gradient values and available atomic hyperfine splittings is in excellent agreement with molecular data. Due to the availability of the hyperfine constants for unstable isotopes of Bi, current atomic calculation allows also to correct their quadrupole moments.