Angular Momentum Projected Potential-energy-surface Calculation: Application to ¹⁷⁸Hf

An angular momentum projected potential-energy-surface (PES) calculation, which takes both rotation symmetry restoration and multi-quasiparticle excitation into account, is developed by using the macroscopic-microscopic model and the projected shell model (PSM). Within this method, it may become possible to modify the excitation spectra which are influenced by shape-softness of nuclei, including high-K states. As our first example, this method is adopted to study the collective and multi-quasiparticle excitations of ¹⁷⁸Hf, and the results are in good agreement with the existing experimental data. In addition, as for the dominant structure of non-collective 6⁺ bands, the conflict between experimental result and the previous PSM calculation is clarified.