On the strong influence of inner shell resonances upon the outer shell photoionization of endohedral atoms

It is demonstrated by the example of the Xe atom stuffed inside the C$_{60}$ fullerene, i.e. the endohedral Xe@C$_{60}$, that the so-called confinement resonances in $4d$-subshell strongly affect the photoionization cross-section of outer $5p$- and subvalent $5s$-electrons near $4d$ ionization threshold. It is a surprise that these narrow inner $4d$ shell resonances are not smeared out in the outer shell photoionization cross-section. On the contrary; the inner shell resonances affect the outer cross-section by enhancing them enormously. Close to its own photoionization thresholds, $5p$ and $5s$ photoionization cross-sections of Xe@C$_{60}$ are dominated by their own confinement resonances greatly affected by the amplification of the incoming radiation intensity due to polarization by it of the C$_{60}$ electron shell. In between $4d$- and $5p$-thresholds, the effect of $4d$ is becoming stronger while own resonances of $5p$ and $5s$ are becoming much less important.