Theoretical Studies On The Energy Level Structure And Radiative Transition Properties Of Lithium-Like Ions

The study of the level structure and transition probabilities for the Lithium-likeions is extremely important in atomic physics. Not only to test high-precision atomicstructure theory, but also to reveal the dynamical properties and the interactionmechanism of complex atoms in the strong Coulomb field is important.The thesis maily studied the energy level structure and transition probabilities oflithium atom and lithium-like ions, contains the following two aspects of researchwork:The transition energies, probabilities, and oscillator strengths for the electricdipole （E1） transitions between all levels of the ground state and the low-lying excitedstates of1s2nl(n=2-4,l=s,p,d,f configurations of Li atom and Li-like ions(Be⁺、C³⁺、O⁵⁺、Ne⁷⁺、Ar¹⁵⁺、Fe²³⁺、Mo³⁹⁺、W⁷¹⁺、U⁸⁹⁺) have been calculated, using therelativistic atomic computational code GRASP2K, which based on theMulti-configuration Dirac-Fock （MCDF） method. The norelativistic results for all ofthose transitions have been also obtained for comparative purposes by performing thesimilar calculations in the non-relativistic limit. The effects of relativity on the E1transition energies and oscillator strengths of Li-like isoelectronic sequence arediscussed with a particular emphasis, and some important conclusions are drawn.Comparison of the present results with other available data is also made, goodagreement is obtained.The influence of plasma screening on the1s²2s_1/2-1s²2p_1/2,3/2and1s²2s_1/2-1s²3p_1/2,3/2electric dipole （E1） transition energies and absorption oscillatorstrengths is investigated theoretically for lithium atom and several ions along thelithium isoelectronic sequence (Be⁺、B²⁺、C³⁺、O⁵⁺、Ne⁷⁺、Ar¹⁵⁺、Fe²³⁺、Mo³⁹⁺、W⁷¹⁺、U⁸⁹⁺). For the case of a weakly coupled hot plasma, multi-configurationDirac-Fock （MCDF） method have been carried out for these ions by considering aDebye–Hückel potential for both the electron-nucleus and electron-electroninteraction. The relativistic effects, electron correlation effects and weak coupledplasma screening effects can be included by the modified GRASP2K package. The variations of the transition energies and oscillator strengths with theplasma screening parameters μ, and the coupling effects of relativistic and plasmascreening on the energy level structure of the sequence ions have been discussed.