Multiple triaxial bands and abnormal signature inversion in As 33 74

摘要

Excited states of the odd–odd nucleus74As have been investigated via heavy ion fusion evaporation reactionZn70(Li7,3n)As74at beam energy of 30 MeV. The properties of the positive- and the negative- parity bands can be interpreted in terms of the Cranked Nilsson–Strutinsky (CNS) model calculations which show that the observed bands are built on the triaxial deformed shape. The inversion of the favored and unfavored signature branches observed in the positive-parity bands presents at high spins rather than normal signature inversion occurs at low spins. This phenomenon may be explained as the origin of unpaired band crossing in a highly rotating triaxial nucleus.