Generalized oscillator strengths for the 3d electrons of Cs, Ba, and Xe:: Effects of spin-orbit-activated interchannel coupling

This paper investigates for the first time ever the use of the spin-orbit interaction to probe correlation effects in the generalized oscillator strength (GOS) of the 3d subshells of Cs, Ba, and Xe, viz. we study how the GOSs of the Cs, Ba, and Xe 3d(3/2) and 3d(5/2) levels are affected by the intradoublet correlations. The calculations are carried out using the Hartree-Fock approximation and within the framework of a modified version of the spin-polarized random phase approximation with exchange, which takes into account multielectron correlation effects. The effects of relaxation of the excited electrons due to the creation of the 3d vacancy are also accounted for. Our GOS results for Cs, Ba, and Xe, obtained for values of the momentum transfer q from 0 to 4 a.u. and energy transfer omega from 0.1 to 8 Ry, demonstrate the strong interaction between the components of the spin-orbit doublet of the 3d electrons in Cs, Ba, and Xe. This leads to the appearance of an additional maximum in the GOS for the 3d(5/2) subshell, due to the action of the 3d(3/2) electrons. Additionally, for the dipole transition in Cs and Ba, the 3d(5/2) subshell perturbs the 3d(3/2) strongly for q=4 a.u. only, while in Xe, the perturbation is at the omega value of approximately 58 Ry for all considered q values. It is concluded that the intradoublet correlations are generally very important in the dipole, monopole, and quadrupole transitions, but particularly in the dipole transition.