Electric quadrupole moments of the Kπ = 8- and 23/2- isomeric states in 170,171,172Hf

The spectroscopic quadrupole moments of the Kπ = 8- isomers in 170Hf and 172Hf, Qs = 4.91(17) b and 5.40(19) b, respectively and Qs = 4.92(17) b for Kπ = 23/2- in 171Hf have been measured using the time differential perturbed angular distribution technique. The nuclear reaction 160Gd(16O, xnγ) was used to excite the respective isomeric states and for the recoil implantation of Hf nuclei into the Hf foil. The quadrupole deformation for the 8- isomer and the ground state has the same value. The deformation corresponding to 23/2- isomeric state is observed to be reduced with respect to the ground state due to the i13/2 neutron alignment. The results are in good agreement with the multi-quasiparticle calculations.