High spin states in ${}^{73}\mathrm{As}$ have been investigated through the fusion-evaporation reaction ${}^{64}\mathrm{Ni}({}^{12}\mathrm{C},p2n){}^{73}\mathrm{As}$ with an incident beam energy of 55 MeV. The level scheme has been extended up to $J^{\pi }=(37/2^{-})$ and excitation energy $\sim 8.7$ MeV with the addition of 30 new $\gamma$-ray transitions. The microscopic origins of the observed positive- and negative-parity band structures are discussed in the context of the particle rotor model. Nucleon alignments and shape evolution with increasing angular momentum are discussed in the framework of the cranked shell model and relativistic mean-field calculations. The results offer insight into the nature of the observed band structures and indicate prolate-oblate shape coexistence between positive- and negative-parity bands at low spin.

• Received 29 September 2015

DOI:https://doi.org/10.1103/PhysRevC.92.064324