It was demonstrated that the Auger decay rate in an endohedral atom was very sensitive to the atom's location in the fullerene cage. Two additional decay channels appeared in an endohedral system: (a) the channel due to the change in the electric field at the atom caused by the dynamic polarization of the fullerene electron shell by the Coulomb field of the vacancy and (b) the channel within which the released energy was transferred to the fullerene electron via the Coulomb interaction. The relative magnitude of the correction terms was dependent not only upon the position of the doped atom but also upon the transition energy ω. Additional enhancement of the decay rate appeared for transitions whose energies were in the vicinity of the fullerene surface plasmons energies of high multipolarity. It was demonstrated that in many cases the additional channels could dominate the direct Auger decay resulting in pronounced broadening of the atomic emission lines. A case study showed that narrow auto-ionizing resonances could be dramatically broadened if the ion was located strongly off-centre. Using the developed model, quantitative analysis of the photo-ionization spectrum for an endohedral complex was carried out and it was demonstrated that the additional channels were partly responsible for the strong modification of the photo-ionization spectrum profile detected experimentally by Müller et al.

Vacancy Decay in Endohedral Atoms: the Role of an Atom's Non-Central Position. A.V.Korol, A.V.Solovyov: Journal of Physics B, 2011, 44[8], 085001