It is shown how the u(3)-boson model with a nonscalar su(3) lowest-weight state can generate low-lying rotational bands and that it does so by the addition of vorticity degrees of freedom to the Bohr-Mottelson irrotational flow model. The model is applied to ${}_{}{}^{20}{}_{}{}^{}\mathrm{Ne}$ with a $(\lambda ,\mu )=(8,0)\mathrm{}$ lowest-weight state and compared both with experiment and with its fully microscopic $\mathrm{sp}\mathrm{}\left(3R\right)\mathrm{}$ counterpart. It is shown that one can easily obtain $B\left(E2\mathrm{}\right)\mathrm{}$ values with the experimentally required enhancements over the simple su(3) model.

NUCLEAR STRUCTURE sp(3,R), sp(6,R), su(3), collective theory, boson models.

• Received 22 January 1982

DOI:https://doi.org/10.1103/PhysRevC.25.3236