Hyperfine Structure of Praseodymium-142

The hyperfine structure of 19-hr Pr¹⁴² in the electronic ground state ⁴I9/2 has been studied by the atomic-beam magnetic-resonance method. The following results have been obtained: electronic splitting factor gJ(⁴I9/2)=-0.7322(3), nuclear spin $I=2$, magnetic-dipole hyperfine-structure constant $|A|=67.5(5)$ Mc/sec, electric-quadrupole hyperfine-structure constant $|B|=7.0(2.0)$ Mc/sec, and B/A>0. From the hyperfine-structure constants, and assumptions made concerning the electronic fields at the nucleus, the nuclear moments are calculated to be |μI|=0.297(15) nm, and $|Q|=0.035(15)$ b, with QμI>0.