Nuclear deformation of holmium isotopes

Abstract

Hyperfine structures and isotope shifts of holmium isotopes and isomers in the mass range 152–165 have been measured for the atomic transition of 592.17 nm using resonance ionization Spectroscopy. Nuclear magnetic dipole and electric quadrupole moments, and changes in mean square charge radii have been derived from the results. Nuclear spins for some isotopes and isomers have been determined too. A sudden change of nuclear deformation between N = 89 and N = 90 has been found. The experimental data are discussed within the framework of the macroscopic-microscopic approach and the Hartree-Fock method. The intrinsic quadrupole moments, including their change at N = 89–90, are described fairly well. At the same time, some difficulties in the description of the mean square charge radii by the Hartree-Fock theory have been revealed.