Attosecond time delay in the photoionization of endohedral atoms A@C$_{60}$: A new probe of confinement resonances

摘要

The effects of confinement resonances on photoelectron group delay (Wignertime delay) following ionization of an atom encapsulated inside a C$_{60}$ cagehave been studied theoretically using both relativistic and non-relativisticrandom phase approximations. The results indicate clearly the resonantcharacter of the confinement oscillations in time delay of the $4d$ shell ofXe@C$_{60}$ and present a most direct manifestation of Wigner time delay. Theseoscillations were missed in a previous theoretical investigation of Ar@C$_{60}$[PRL 111, 203003 (2013)]