Prominent conjugate processes in the PCI recapture of photoelectrons revealed by high resolution Auger electron measurements of Xe*

The Xe ($N_{\mathrm{5}}O_{\mathrm{2,3}}O_{\mathrm{2,3}})$ Auger electron spectrum originating from 4$d^{\mathrm{-1}}_{\mathrm{5/2}}$ photoionization was measured with the photon energy tuned very close above the ionization threshold. As the photon energy approached the 4$d^{\mathrm{-1}}_{\mathrm{5/2}}$ photoionization threshold, Rydberg series structures including several angular momentum components were formed within the Auger profile by the recapture of the photoelectrons into high-lying final ion orbitals. Our spectrum with resolution much narrower than the lifetime width of the corresponding core excited state allowed us to resolve detailed structures due to the orbital angular momenta very clearly. Unexpectedly, conjugate peaks originating from the exchange of angular momentum between the photoelectron and the Auger electron through Post-Collision-Interaction were found to dominate the spectrum. The new assignments were in accord with the quantum defect values obtained for the high Rydberg series for singly charged ionic Xe$+$5$p(^{\mathrm{1}}S_{\mathrm{0}})$\textit{ ml}.