Hyperfine Structure Analysis for the Ground Configuration of Bismuth

Abstract

An analysis of the magnetic and electric hyperfine structure has been performed for the 6p3 configuration of 209Bi by use of an effective hyperfine structure Hamiltonian. For the magnetic hyperfine structure, experimental mean values of r-3 exist for the orbital, spin-dipole and spin terms of the Hamiltonian. Theoretical mean values of r-3 obtained from relativistic self-consistent-field (SCF) wavefunctions are in good agreement with the experimental orbital and spin-dipole values of ⟨r-3⟩, while relativistic effects can only explain about 50% of the experimental spin part. This discrepancy is mainly due to core polarization, which has been estimated by use of non-relativistic unrestricted SCF wavefunctions. The core polarization contribution has been corrected for relativistic effects using correction factors obtained from a comparison between relativistic and non-relativistic restricted SCF wavefunctions. Most of the spin part of the hyperfine interaction can be explained in this way. By use of hyperfine radial integrals obtained from relativistic SCF wavefunctions the quadrupole and octupole moments have been evaluated with the result: Q = -0.46 b. (Sternheimer uncorrected) and Ω = 0.62(8) n.m.b. respectively.