We suggest that, within the framework of the interacting-boson model, the group O(6) of orthogonal transformations in six dimensions may be useful in classifying nuclear spectra at the end of major shells. We derive analytic expressions for the energy levels and electromagnetic transition rates in this limit.

• Received 9 December 1977

DOI:https://doi.org/10.1103/PhysRevLett.40.385