The subtle effect of vdW interactions upon the C60 fullerene structure

The experimental data seem to suggest that the C60 fullerene shrinks slightly in the nearby presence of nonbonding molecules. This paper reports on extensive calculations aiming at confirming this effect. The first tests were done on the C60-benzene complex, where we found that indeed C60 shrinks slightly for certain conformations of the approaching benzene. The presence of more that one benzene molecule strengthens the effect upon the fullerene making it clear that the effect is cumulative. The fact that even single benzene molecule at a distance much larger than equilibrium causes the fullerene to shrink indicates that the shrinking effect is long-ranged. Our investigations exclude the possibility of numerical errors in calculations as the source of the observed shrinking. The main goal of this paper is to understand the role of van der Waals interactions in the variations of the C60 radius.