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

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