Study On Transitional Region Of The Interacting Boson Model With The Three-body Term

The Interacting Boson Model(IBM) is one of the most significant models in theory of nuclear structure.Investigation on properties of the model is of importance.In this thesis,a Fortran code for numerical computation of the matrix elements in the SU(3) symmetry-adapted basis for the IBM with three-body term is given.In virtue of the program,the relation between the model Hamiltonian and the former triaxial rotor model,triaxial deformation and quantum phase transition behaviors in transitional region are studied in detail.Results with respect to both overall and special situations of the model are discussed.Quantum phase transitional behavior under variety of parameter situations is also studied.Most importantly,it is found that transitional behavior of excited states are more complicated.Dy,Er,and Os isotopes are taken as examples in illustrating the results.