Research On Neutron-Rich Nuclei Using A Particle Number Conserving Method Based On Cranked Shell Model

In recent years,due to the extensive application of radioactive detecting devices in nuclear experiments,it makes possible to study the structure of neutron-rich nuclei far from theβ-stability line.The in-beam spectroscopy of the neutron-rich nuclei in rare earth region has been fruitfully investigated.These nuclei are well deformed.The study of these nuclei is certainly also very interesting in itself.The rotational spectra in these nuclei can reveal detailed information on the singleparticle configurations,the shell structure,the stability against rotation,thus providing a benchmark for nuclear models.The rotational bands in neutron-rich odd-A nuclei in rare-earth region,are investigated systematically by using a cranked shell model（CSM）with the pairing correlations treated by the PNC method.The single particle level is calculated using the Nilsson Hamiltonian.The traditional Nilsson parameters（κandμ）are optimized to reproduce the experimental level schemes for the rare-earth and actinide nuclei near the stability line.However,this parameter set can not describe well the experimental level schemes of transfermium nuclei.By fitting the experimental single-particle spectra in these nuclei,a new set of Nilsson parameters（κandμ）are proposed.The bandhead energies of the 1-quasineutron bands in odd-A nuclei are reproduced quite well by the PNC-CSM calculation using this parameter set.The root-mean-square deviations of theoretical1-qp bandhead energies from the experimental values are about 320 keV,which are much better than those calculated by using the traditional Nilsson parameters.In the PNC-CSM,the rorational bands in neutron-rich nuclei are investigated systematically.By analyzing the cranking frequency dependence of the occupation probability of each cranked Nilsson orbital near the Fermi surface and the contributions from high-j orbitals in each major shell to the kinematic moments of inertia,the backbending mechanism is explained clearly.Besides,the relative even-odd differences of the bandhead moments of inertia in Hf isotope are calculated briefly,which exist greatly large scale fluctuations,and this is in accord with experiments.Namely,δJ/J depends sensitively on the Nilsson level location of the blocked orbital in the odd-N nuclei.When high-j and lowΩintruder obital near the Fermi surface is blocked,δJ/J is very large.There are few experimental data on the experimentally obtained rare earth region odd proton nuclei.Recently,experimentally observed rotating belts of ¹⁶³Eu,we have studied these nuclei using the PNC-CSM method,and the calculation results are in good agreement with the experimental data（if using above new parameters,the result will be better）.It can be conclude that the calculated high-K isomeric band head energy with non-zeroε₆ are much more consistent with experimental values than calculations withoutε₆.The high order deformationε₆ plays an important role in nuclear structure of ¹⁶³Eu.964（1）keV 13/2^-was designatedν7/2⁺[633]?ν1/2^-[521]?π5/2⁺[413].In addition,we also calculate pairing gaps of ¹⁶³Eu.Compared with the neighboring even-even nuclei,the pairing gaps of the odd-A nuclei is lower than neighboring even-even nuclei atω=0.