Photoionization of endohedral atoms using R-matrix methods: Application to Xe@C-60

Abstract

It is demonstrated that the effect of a static cage potential on the photoionization of endohedrally enclosed atoms can be incorporated into standard R-matrix calculations using one of two independent methods. For photoionization processes occurring entirely within the fullerene, the outer-region solutions can be modified by the additional cage potential to yield phase-shifted Coulomb functions that are matched to the inner-region R matrix. Alternatively, if the cage potential is contained within the R-matrix "box," it can be directly incorporated into the formalism via simple one-electron integral contributions to the Hamiltonian, yielding a modified R matrix. Both methods are applied to the photoionization of Xe@C-60 in the vicinity of the giant 4d -> epsilon f shape resonance and are found to be in excellent agreement with each other.