Revivification of confinement resonances in the photoionization of $A$@C$_{60}$ endohedral atoms far above thresholds

TL;DR

This paper theoretically demonstrates that confinement resonances in the photoionization of endohedral atoms can reappear and become strong at high photon energies far above ionization thresholds, revealing a new general phenomenon.

Contribution

It uncovers the phenomenon of re-emerging confinement resonances at high energies in multielectron endohedral atoms, supported by a case study of Ne@C60.

Findings

Confinement resonances can reappear at high photon energies.

Re-emergence of resonances is a general phenomenon.

Case study confirms the theoretical prediction.

Abstract

It is discovered theoretically that significant confinement resonances in an $nl$ photoionization of a \textit{multielectron} atom $A$ encaged in carbon fullerenes, A@C$_{60}$, may re-appear and be strong at photon energies far exceeding the $nl$ ionization threshold, as a general phenomenon. The reasons for this phenomenon are unraveled. The Ne $2p$ photoionization of the endohedral anion Ne@C$_{60}^{5-}$ in the photon energy region of about a thousand eV above the $2p$ threshold is chosen as case study.