Nuclear electric quadrupole moment of bismuth from the molecular method

Abstract

Electric-field gradients at bismuth nuclei in BiN and BiP molecules were determined from relativistic Dirac-Coulomb calculations by means of the coupled cluster approach with single and double substitutions with perturbative triple excitation corrections CCSD(T) and CCSD-T approaches. These theoretical values were combined with accurate experimental nuclear quadrupole coupling constants in order to obtain the nuclear electric quadrupole moment (NQM) of the ${}^{209}$Bi nucleus. Our best results indicate an NQM of \ensuremath{-}420(8) mb, which considerably deviates from the previously accepted standard value given by the atomic method \ensuremath{-}516(15) mb.