Two-photon resonance single ionization of the K-shell of an atomic ion

The analytical structure and absolute values of the generalized cross-section of the two-photon resonance single ionization of the K-shell of a heavy neon-like ion of an iron atom (Fe$^{16+}$) were theoretically predicted. A pronounced resonant subthreshold structure of the generalized cross-section and the effect of destructive quantum interference of the probability amplitudes of radiation transitions into virtual excited states of p-symmetry have been established. The presence of a valence 2p$^6$-shell in the ion backbone causes the production of an additional giant resonance of the generalized cross-section as the effect of the "reverse" hard X-ray emission of K$\alpha$-type 1s$^2$(2s$^2$)2p$^5$ + $\hbar\omega \to$ 1s(2s$^2$)2p$^6$. A scheme of the proposed experiment with linearly polarized X-ray photons is presented to verify the theoretical results obtained.