Electric quadrupole moments of the K π = 8? and 23/2? isomeric states in 170, 171, 172Hf

The spectroscopic quadrupole moments of the K ^π = 8^? isomers in ¹⁷⁰Hf and ¹⁷²Hf, Q _s ?=?4.91(17) b and 5.40(19) b, respectively and Q _s ?=?4.92(17) b for K ^π ?=?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 i _13/2 neutron alignment. The results are in good agreement with the multi-quasiparticle calculations.