We further characterized the interaction strength between the constituent monomers in the 2C60@Cn trimer using interaction energy From the interaction between two C60 fullerenes and cyclocarbon ( be seen that the medium-sized C22 and C26 interact most strongly with fullerenes, the C18 interacts weakly due to its smaller number of atoms, and the C30 interacts less strongly due to its loose binding with one of the fullerenes. The deformation energy in Fig. (b) indicates that the larger the carbon ring, the more likely it is to increase the system energy due to structural change during formation of the 2C60@Cn trimer. But even for 2C60@C30 with the maximum deformation energy, this value is only about 1.0 kcal/mol, which creates negligible hindrance to the complexation. The vdW potential proposed by one of us is a particularly useful method for intuitively understanding vdW interaction between a molecule of interest and surrounding molecules. Here, we use the vdW potential based on the Lennard-Jones parameters of Generation Amber Force Field (GAFF) forcefield to delve into how the cyclocarbon acts as a "glue" to aid in the binding of two C60 fullerenes. Carbon is used as the probe atom, and complexes 2C60@C22 and 2C60@C30 are taken as examples. The vdW potentials generated by the cyclocarbon in these two systems are plotted as isosurface maps and colored section maps in Fig. . In Fig. (a), the atoms in fullerenes are colored according to the vdW potential-the bluer the color, the more negative the vdW potential, and the stronger the dispersion attraction from the cyclocarbon felt by the corresponding fullerene atoms. From the maps of 2C60@C22, it can be intuitively seen that the region where the vdW potential generated by C22 is obviously negative, that is, the region where the dispersion attraction interaction greatly exceeds the exchange-repulsion effect, mainly covers the axial area near the center of C22 with slight outward extension at both ends. This region simultaneously covers more than one-third of atoms in the two C60 fullerenes.