Spectroscopic study of the possibly triaxial transitional nucleus 75Ge

Abstract

The collective structures of 75 Ge have been studied for the first time via the 74 Ge(α,2p1n) 75 Ge fusionevaporation reaction. Two negative-parity bands and one tentative positive-parity band built on the νp 1/2 , νf 5/2 , and νg 9/2 states, respectively, are established and compared with the structures in the neighboring N = 43 isotones. According to the configuration-constrained potential-energy surface calculations, a shape transition from oblate to prolate along the isotopic chain in odd-A Ge isotopes is suggested to occur at 75 Ge. The properties of the bands in 75 Ge are analyzed in comparison with the triaxial particle rotor model calculations.