Sensitivity of cross sections to the diffuseness of the confining potential in time-dependent close-coupling calculations of the double photoionization of He@C60

Abstract

Calculations of the photoionization of endofullerenes often use a square-well potential to represent the confining fullerene. The sensitivity of the photoionization cross sections to the form of this model potential is explored here by the use of a diffuse potential. The cross sections for single photoionization with excitation and double photoionization of He@C${}_{60}$ are found to show damping of the confinement resonance structure as the degree of diffuseness is increased using a commonly adopted well depth of 8.22 eV. For a deeper well depth of 11.00 eV, the double-photoionization cross section is found to be insensitive to the diffuseness of the confining potential, as has also been reported recently for the single photoionization of H@C${}_{60}$ and Xe@C${}_{60}$ [Dolmatov, King, and Oglesby, J. Phys. B 45, 105102 (2012)].