Calculation and evaluation of energy levels and radiative rates for 2s22p6-2s2p6np and 2s22p6-2s22p5nd(4≤n≤20) transitions in Cu XX

Energy levels, oscillator strengths, and radiative rates have been calculated for 2s22p6-2s2p6np and 2s22p6-2s22p5nd transitions with 4≤n≤20 in Cu XX ions. In the calculations, the Flexible Atomic Code has been used, and systematic analysis and evaluation of the accuracy of the calculated results for the two types of transitions are also given with different indicators. It is shown that the results for the transitions with a 2s hole are greatly improved by using the present method comparing to those from RELAC code. Furthermore, our results show that the energy levels of the 2s2p6(n+1)l and 2s22p5(n+2)l configurations closely interact with those of the 2s2p6np series and it is essential to include the 2s22p5(n+1)l configurations in the calculations for the 2s22p5nd series.