Perturbed alignments within ani13/2neutron intruder band inGd141

The nucleus ${}_{}{}^{141}{}_{}{}^{}\mathrm{Gd}$ was investigated at high spins for the first time via the reactions ${}_{}{}^{112}{}_{}{}^{}\mathrm{Sn}$ ${(}^{32}$S,2pn${)}^{141}$Gd at 155 MeV and ${}_{}{}^{112}{}_{}{}^{}\mathrm{Sn}$ ${(}^{33}$S,2p2n${)}^{141}$Gd at 170 MeV. The methods of in-beam γ-ray spectroscopy were used to establish a number of different structures. These include a band assigned as the ν${\mathit{i}}_{13/2}$[660]1/$2^{+}$ intruder in the Nilsson scheme. This is the heaviest nucleus thus far in which this type of intruder band has been identified, and is the first case in which the 13/$2^{+}$ bandhead has been clearly observed. Cranked shell model (CSM) calculations predict the occurrence of backbends due to ${\mathit{h}}_{11/2}$ proton and ${\mathit{h}}_{9/2}$ neutron band crossings. Gradual upbends are observed in the experimental alignments, which suggests the interaction strengths are stronger than those predicted by the CSM.