Diffuse versus square-well confining potentials in modelling A@C60 atoms

A perceived advantage for the replacement of a discontinuous square-well pseudo-potential, which is often used by various researchers as an approximation to the actual C-60 cage potential in calculations of endohedral atoms A@C-60, by a more realistic diffuse potential is explored. The photoionization of endohedral H@C-60 and Xe@C-60 is chosen as the case study. The diffuse potential is modelled by a combination of two Woods-Saxon potentials. It is demonstrated that photoionization spectra of A@C-60 atoms are largely insensitive to the degree eta of diffuseness of the potential borders, in a reasonably broad range of eta s. These spectra are found to be insensitive to discontinuity of the square-well potential as well. Both potentials result in practically identical calculated spectra. New numerical values for the set of square-well parameters, which lead to a better agreement between experimental and theoretical data for A@C-60 spectra, are recommended for future studies.