Computational Exploration of Xe Dimers Inside Fullerene Cages

A systematic analysis for the determination of the optimum fullerene cage for encapsulation of xenon dimers was carried out using density functional theory and activation strain analysis. Our calculations indicate that tubular-like fullerenes are better candidates for the encapsulation of xenon atoms. However, the tubular-like structure should have at least a diameter that is proportional to the van der Waals radius of encapsulated atoms. Our calculations indicate that the smallest fullerene that can stabilize the encapsulation of the xenon dimers in an energetically favorable dimeric state is Xe₂@C₁₂₀ ([10,0] C₁₂₀-<i>D</i>_5<i>h</i>(10766)). When going to higher order fullerenes, the dispersion interaction will dominate over all other interactions. However, the additional space provided by the tubular-like fullerene leads to elongation of the distance between the encapsulated xenon atoms, thus hampering the formation of a xenon-xenon chemical bond.