Formation of dimers of light noble atoms under encapsulation within fullerene’s voids

Van der Waals (vdW) He(2) diatomic trapped inside buckminsterfullerene’s void and preserving its diatomic bonding is itself a controversial phenomenon due to the smallness of the void diameter comparing to the He-He equilibrium distance. We propound a computational approach, including smaller fullerenes, C(20) and C(28), to demonstrate that encapsulation of He(2) inside the studied fullerenes exhibits an interesting quantum behavior resulting in a binding at shorter, non-vdW internuclear distances, and we develop a computational model to interpret these He-He bonding patterns in terms of Bader’s atom-in-molecule theory. We also conjecture a computational existence of He(2)@C(60) on a solid basis of its theoretical UV absorption spectrum and a comparison with that of C(60).