The high-spin parts of shears bands observed in ${}^{198,199}\mathrm{Pb}$ are described by coupling several valence particles to a deformed rotor core. To give the model enough freedom so that both the proton and the neutron spin vectors can find their preferred direction, the use of five to six valence particles and holes is found to be necessary. Effective parameters characterizing the rotor are deduced from the cranking model. The method is described and results are presented concerning transition probabilities and energies in the high-spin regime for several rotational bands in ${}^{199}\mathrm{Pb}$. The possible termination of the rotational bands is also discussed.

• Received 9 June 2006

DOI:https://doi.org/10.1103/PhysRevC.74.044310