Reexamination of nuclear magnetic dipole and electric quadrupole moments of polonium isotopes

We reexamined the electronic structure parameters used to interpret the hyperfine structure of neutral polonium. We used a computational scheme that treats relativistic and high-order electronic correlation effects within the coupled cluster with single, double, triple, and perturbative quadruple excitations (CCSDT(Q) method), as well as estimated the contribution of quantum electrodynamics and finite nuclear size effects. A systematic study of the uncertainty is carried out. This allowed us to obtain significantly refined values for the nuclear magnetic dipole and electric quadrupole moments of a wide range of odd-mass polonium isotopes. For ²⁰⁵Po and ²⁰⁷Po we extracted both the magnetic moment and the nuclear magnetization distribution parameter in a nuclear model-independent way. To assess the accuracy of the calculations, we also computed the ionization potential (IP), excitation energies (EEs) of the 6p⁴0.16em0ex¹D₂ and 6p³7s¹0.16em0ex⁵S₂ electronic states, and the electronic gJ factor in the same theoretical framework. A good agreement of the theory and experiment for IP, EEs, and gJ confirms the reliability of the computational scheme and uncertainty estimation for the Po electromagnetic moments. We identify the 6p⁴0.16em0ex¹D₂ electronic level as a potentially promising state for further studies of the nuclear moments of polonium isotopes.