The ${}^{105}\mathrm{Rh}$ nucleus has been studied with the ${}^{100}\mathrm{Mo}\left({}^{11}\mathrm{B},\alpha 2n\gamma \right)$ reaction at $43\text{MeV}$ incident energy. A rich variety of structures was observed at high and low spins, using $\gamma \text{−}\gamma \text{−}t$ and $\gamma \text{−}\gamma \text{−}\mathit{particle}$ coincidences and directional correlation ratios. A $\gamma$-vibrational band was observed for the first time in this nucleus. A new structure based on the intruder $1∕2^{+}$[431] proton orbital was identified. Four magnetic dipole bands have also been observed at high spin, three of which have negative parity and have similar characteristics: they are very regular in energy spacing, presenting nearly constant alignments and large values of $B\left(M1\right)∕B\left(E2\right)$ ratios. Two of them are nearly degenerate in excitation energy and could be chiral partners. The $\pi g_{9∕2}\otimes \nu h_{11∕2}\left(g_{7∕2},d_{5∕2}\right)$ configuration is tentatively assigned for these bands, with the angular momenta of the proton and neutron intruders and the collective angular momentum aligning along the three perpendicular axes of the triaxial core, as predicted by tilted axis cranking calculations.

• Received 14 July 2003

DOI:https://doi.org/10.1103/PhysRevC.69.024317