Theoretical Research On The Energy Structure And Oscillator Strength Of Excited States For Cr～(21+) Ion

The history and the present conditions of the atomic physics are synoptically reviewed; highly ionized atomic systems are frequently met in the study of the experiment physics, astrophysics and nuclear physics, the study of them is of great benefit of the development of the related experiment and theoretic physics. The property of the lithium-like atoms, especially, the ions of three electrons with 1s2-core is important because of their particularity. In this paper, FCPC method is extended to calculated the energy structures and oscillator strengths of 1s2nl (l = s, p) states for Cr21+ ion. The non-relativistic energies and wave functions are calculated by using Rayleigh-Ritz's variation method. The relativistic and mass-polarization effects on the energies are calculated as the first-order perturbation. The quantum-electrodynamics contributions are evaluated by using effective nuclear charges. The fine structure is determined by calculating the expectation values of the spin-orbit and the spin-other-orbit interaction operators.The quantum defects of 1s2nl (l = s, p;n≤9) Rydberg series for Cr21+ ion are determined by the single-channel quantum defect theory. The energies of any highly excited states with n≥10 also can be reliably predicted by using the quantum defects which are function of energy. The dipole oscillator strengths for the 1s2ns-1s2np (n≤9) transitions of Cr21+ ion are calculated with the transition energies and FCPC wave functions obtained above. Combining the quantum defect theory with the discrete oscillator strengths, the discrete oscillator strengths for the transitions from the given initial state to highly excited states (n≥10) and the oscillator strengths density corresponding to the bound-free transitions are obtained.