Photoionization of onion-type atoms

The photoionization of a two-shell ("onion") endohedral A@C(N1)@C(N2) is considered. The effect of the fullerenes shells upon photoelectron from atom A is taken into account substituting the action of the fullerene by two zero-thickness "bubble potentials." The fullerenes shells polarization is included assuming that the radius of the outer shell R (2) is much bigger than the inner R (1) and both much exceed the atomic radius r. The interaction between shells C(N1) and C(N2) is taken into account in the Random Phase Approximation (RPA). The effect of photoelectron scattering by both "bubble potentials" is included in the RPA frame. As concrete examples, two endohedrals Ar@C(60)@C(240) and Xe@C(60)@C(240) are considered. We investigate 3p4 Ar and 5p Xe subshells.