First exploration of wobbling modes in an isotone chain: The N=59 case

The possible existence of wobbling modes in the N=59 isotones Kr95, Sr97, Zr99, Mo101, Ru103, Pd105, and Cd107 is explored by the constrained triaxial covariant density functional theory combined with quantum particle rotor model calculations. It is found that there are several states with suitable triaxial deformations and high-j particle configuration to establish wobbling modes in Sr97, Zr99, Mo101, Ru103, and Pd105. The available experimental energy spectra based on the ν(1h11/2)1 configuration in Sr97 and Zr99 are described well. The decreased energy difference between the doublet bands, the enhanced B(E2)out/B(E2)in values, as well as the one-phonon oscillation characteristic of the total angular momentum indicate that the two nuclei can be transverse wobbling candidates, which suggests the possibility of a larger region of wobbling modes near the A≈100 mass region.