To describe obvious intruder states and nonzero quadrupole moments of γ-soft nuclei such as Pt194, a rotor extension plus intruder configuration mixing with 2n-particle and 2n-hole configurations from n=0 up to n→ in the O(6) (γ-unstable) limit of the interacting boson model is proposed. It is shown that the configuration mixing scheme keeps the lower part of the γ-unstable spectrum unchanged and generates the intruder states due to the mixing. It is further shown that almost all low-lying levels below 2.17 MeV in Pt194 can be well described by modifying the O(6) quadrupole-quadrupole interaction into an exponential form. The third-order term needed for a rotor realization in the interacting boson model seems necessary to produce nonzero quadrupole moments with the correct sign.
Publication Source (Journal or Book title)
Physical Review C
Pan, F., Yuan, S., Qiao, Z., Bai, J., Zhang, Y., & Draayer, J. (2018). γ -soft rotor with configuration mixing in the O(6) limit of the interacting boson model. Physical Review C, 97 (3) https://doi.org/10.1103/PhysRevC.97.034326