ABINITIO CALCULATIONS OF TETRAHEDRAL HYDROGENATED BUCKMINSTERFULLERENE

The equilibrium geometries and relative stabilities of C60H12n (n = 1-5) molecules in T(h) symmetry are studied at the Hartree-Fock level of theory employing basis sets of double-zeta quality. Hydrogens were allowed to attach to carbon atoms both from the outside (exo-hydrogenation) and the inside (endo-hydrogenation ) of the C60 cage. In the totally exo-hydrogenated case, it is found that C60H36 and C60H48 are the most stable molecules in the C60H12n series. For C60H60 only, a lower energy isomer is found when 12 H atoms are placed inside the C60 cage. The total energy of this form of C60H60 is much lower than that of the previously predicted I(h) Structure, although it may not be easily accessible due to a large barrier for H penetration of C60.