PSEUDO-SU(3) MODEL AND UNIQUE PARITY STATES

The role of intruder levels in heavy deformed nuclei is investigated i n the framework of the SU(3) shell model. A model system is constructe d which mimics the dynamics of heavy deformed nuclei and allows for th e inclusion of quadrupole-quadrupole, spin-orbit, orbit-orbit, and pai ring interactions without requiring any truncation scheme. Correlation s generated by particles in the unique parity space and by the interac tion of nucleons in the normal parity orbitals with those in unique pa rity levels are shown to play an important role in driving the many-pa rticle system to its maximum allowed deformation. Implications of the results for commonly applied truncation schemes are discussed.