The Algebraic Model Descriptions Of Octupole Deformations Of Nuclei

The interacting boson model(IBM)is a very successful model in describing collective structures of nuclei in the heavy and intermediate-heavy region.In this model,it is assumed that collective properties of quadrupole deformed nuclei are dominated by s bosons of J^P=0⁺ and d bosons of J^P=2⁺,respectively.To describe octupole deformation in nuclei,f bosons of J^P=3^- have to be involved in order to extend the IBM model sapce.In this thesis,new algorithm and program have been developed to solve two kinds of the IBM+f boson model,by which the related experimental data have been fitted and analyzed.The results indicate that the model can give reasonable description of both positive-parity states and negative-parity states in the deformed nuclei in the rare-earth region.In particular,it is shown that the properties of various types of excited states below 2Me V in¹⁵²Sm can be very accurately reproduced in the IBM-2+fboson model,where the neutron and proton degrees of freedom are explicitly distinguished,thus further confirming the values of the IBM+fboson model in understanding the octupole dynamics of heavy and intermediate-heavy nuclei.