Modeling A@C60 atoms: diffuse versus square-well confining pseudo-potentials

An empirical model approximating the C₆₀ cage potential by a square-well confining potential has played an important role in providing the initial understanding of photoionization spectra of A@C₆₀ endohedral atoms [1]. However, the square-well potential is discontinuous at its boarders. A more realistic confining potential must be diffuse, obviously. However, it is not at all clear apriori to what degree replacement of a square-well potential by a diffuse potential may alter predictability of the model. In particular, should a large array of predicted data and phenomena made on the basis of a square-well potential model be re-studied with an eye on a more realistic diffuse potential boarders of C₆₀? It will be shown in this presentation, with H@C₆₀ and Xe@C₆₀ as case studies, that both the square-well and diffuse confining potentials lead to practically identical calculated data for A@C₆₀ photoionization spectra. Moreover, the latter are largely insensitive to the degree of diffuseness of the potential, in reasonable limits. Hence, either of said potentials is equally suitable for mimicking the C₆₀ cage.[4pt] [1] V. K. Dolmatov, Adv. Quant. Chem. 58, 13 (2009).