Theoretical Studies On Level Structures And Transition Properties Of Neptunium Ions

Energy resources and environment is the basis of human survival and development. Withthe development of human modernization, the nuclear energy is getting more and moreattention in many countries. However, the large-scale and sustainable development of nuclearenergy is still subject to some important problems, such as nuclear fuel resources, the disposalof long-lived radioactive waste, reactor safety and so on. Analysis showed that the long-termrisk of spent fuel is mainly determined by²³⁷Np,²⁴¹Am,²⁴²Am,²⁴³Am,243Cm,²⁴⁴Cm and²⁴⁵Cm, they are harmful to human and environment. So it is crucial to study of the structureand physicochemical properties of actinides for the treatment the nuclear waste. In this thesis,we investigated the level structures and transition properties of Np³⁺â†'Np⁶⁺by using theGRASP2K package based on multiconfiguration Dirac-Fock（MCDF） method. The mainworks contain：we investigated the ionization potentials, ionic radii, excitation energies for5fN，5f（N-1）6d，5f^{（N-1）}s，5f^{（N-1）}p configurations, oscillator strengths from5f（N-1）6d,5f^{（N-1）}s to5fNfor Np³⁺-Np⁶⁺. In the calculations, the main valence correlation effects was take intoaccount, the core-valence and core-core correlation effects was neglected. Meanwhile, Breitinteraction and QED effects were also neglected because of the contribution of these effectswere very small to the final results. The good consistency with other available theoreticalvalues demonstrates the validity of the present calculations.