A new and explicitly many-body aspect of the “leveraging” of the spin-orbit interaction is demonstrated, spin-orbit activated interchannel coupling, which can significantly alter the photoionization cross section of a spin-orbit doublet. As an example, it is demonstrated via a modified version of the spin-polarized random phase approximation with exchange, that a recently observed unexplained structure in the Xe ${3d}_{5/2}$ photoionization cross section [A. Kivimäki et al., Phys. Rev. A 63, 012716 (2000)] is entirely due to this effect. Similar features are predicted for Cs ${3d}_{5/2}$ and Ba ${3d}_{5/2}$.

• Received 12 June 2001

DOI:https://doi.org/10.1103/PhysRevLett.88.093002