Adsorption of atoms and fluids on spherical surfaces

The adsorption of helium on buckyballs at zero temperature is studied using finite range density functional and path integral Monte Carlo methods. The results include strong binding for ${\mathrm{C}}_n$ fullerenes $(n>~20)$ with a maximum number of adsorbed helium atoms at saturated vapor pressure, and a transition to no adsorption for weakly attractive potentials, exemplified by the case of a small Mg sphere. We show that a simple model describing the film as a continuum characterized by bulk parameters yields predictions in qualitative agreement with the more accurate computations.