Blocking effect and the moments of inertia of high-Kmultiquasiparticle bands in172,173,174,175Hf

Abstract

The series of high-$K$ multiquasiparticle bands in ${}^{172,173,174,175}\mathrm{Hf}$ are investigated using the particle-number-conserving (PNC) method for treating the cranked shell model with monopole and quadrupole pairing interactions. The experimental results, including the moments of inertia and angular momentum alignments relative to the ground state band ${}^{172}\mathrm{Hf}(\mathrm{g}.\mathrm{s}.\mathrm{b}.)$ are reproduced quite well by the PNC calculation, in which no free parameter is involved. The difference in the $\ensuremath{\omega}$ variation of the moments of inertia between the high-$K$ multiquasiparticle bands and ${}^{172}\mathrm{Hf}(\mathrm{g}.\mathrm{s}.\mathrm{b}.)$ is mainly due to the blocking effects of high j intruder orbitals near the Fermi surface. The $\ensuremath{\omega}$ variation of the occupation probability of each cranked orbital and the contribution to moment of inertia from each major shell and from each cranked orbital are investigated.