Towards a Shell Model Description of the Low Energy Structure of Deformed Nuclei. I. Even-Even Systems

摘要

A microscopic shell model theory for the low-lying collective states of heavy deformed nuclei is described. Basis selection is guided by the Bohr-Mottelson-Nilsson picture of collective motion in nuclei. The necessary further truncation is achieved by exploiting an SU(3) symmetry inherent to the structure of the normal parity states and by restricting abnormal parity configuration to states with low seniority. An effective interaction comprised of operators which form an integrity basis for the SU(3) implies R(3) algebra is shown to be sufficient to reproduce almost exactly, within single leading irreducible representation of SU(3), the ground and gamma band rotational structure of eight rare earth ( exp 160 Dy, exp 162 Dy, exp 164 Dy, exp 164 Er, exp 166 Er, exp 168 Er, exp 166 Yb, exp 168 Yb) and four actinide ( exp 232 Th, exp 234 U, exp 236 U, exp 238 U) nuclei. The concomitant interband and intraband E2 strengths are also shown to be accurately reproduced. Extensions of the theory and necessary further theoretical investigations are reviewed. 32 references. (ERA citation 09:015488)