Intra-doublet correlations in 4d subshell of Xe

We demonstrate here that an additional near threshold structure appear due to influence of four 4d3/2 electrons upon the six 4d5/2. This effect is a manifestation of interaction between levels that are initially degenerate after this degeneration is eliminated. Being a relativistic effect, this phenomenon can be treated non-relativistic as well. The energy splitting between spin-orbit components of the 4d level can be taken from experiment and the nature of the 4d5/2 and 4d3/2 splitting is inessential. The approach used is similar to that developed for consideration of intra-doublet correlations between 3d3/2 and 3d5/2 Xe levels. We treated Xe in the non-relativistic RPAE frame, considering the 3d10 as consisting of two groups of spin-up and spin-down electrons. The case of 4d is different from 3d since the spin-orbit splitting in 4d is much smaller --2 eV. We demonstrate that the account of intra-doublet correlations leads to a small maximum close to threshold in 4d5/2 and a prominent variation of the cross-section at 75-81 eV. The variation for 4d3/2 is smaller, but substantial.