The H <sub> 2 </ Sub> @ C, <sub> 60 </ Sub> And Its Dimer Geometry And Electronic Structure Study

The geometric and electronic properties of endohedral H₂ fullerenes C₆₀ and D_2h-C₁₂₀are studied using the generalized gradient approximation (GGA) based on the densityfunctional theory (DFT).We first discuss the existence of the hydrogen as well as it's movement in the carboncage, then analyze it's geometric and electronic structures. The studies show that hydrogenis presented in the form of molecule and the most favorable endohedral site is in the centerof the cage, and the hydrogen molecule can be rotated freely inside the cage. The influenceof the hydrogen on the carbon cage is very small, and each carbon cage can keep the framestructure invariably. The change of the endohedral hydrogen molecule itself is also verysmall, and can be neglected. The calculations for the electronic structures show that whenintroducing the H₂ molecule into the C₆₀ and C₁₂₀, there is small contribution to density ofstate below the fermi energy from - 8eV to -5eV, and other of energy distribute and energygap almost do not change, and the number of the electrons that transfer to the carbon cageis very small. These can also be neglected so that the cage still keeps the original propertyconstantly. All these phenomena is due to the very weak. van der Waals force between thehydrogen molecule and the carbon cage so that when make the hydrogen moleculepointing to the different directions, the effect to the carbon cage is small, and this also canbe took as a proof that it can moves freely in the carbon cage for the hydrogen molecule atthe same time.