Hydrogenated fullerenes dimer, peanut and capsule: An atomic comparison

•The C118 dimer is lower in energy than the energies sum of C60 and C58 cages by 1.77eV.•The energy per carbon atom of C144 capsule is more stable than C60 cage by 126.98meV.•The most reactive hydrogenation sites are Houts1 and Houts3.•13C NMR can be used to distinguish between fullerenes dimer, peanut and capsule. Hydrogenated fullerenes are detected in the Universe in space but their identification is still unsolved task. Therefore, this paper provides useful information about hydrogenated fullerenes (dimer, peanut and capsule) using DFT method at the B3LYP/6-31G(d) level of theory. The stability, geometric structures, hydrogen adsorption energies and NMR chemical shifts are calculated. The results show that the energy of most stable isomer of C118 dimer is lower than the energies sum of C60 and C58 cages by 1.77eV and the energy per carbon atom of C144 capsule is more stable than C60 cage by 126.98meV. Also, endohedral Ti-doped C118 dimer and C128 peanut are found to be most stable structures than exohedral Ti-doped C118 dimer and C128 peanut by 2.19eV/Ti and 3.52eV/Ti, respectively. The hydrogenation process is found to be enhanced (especially at the caps) for endohedral Ti-doped C118 dimer and C128 peanut through electronic surface modifications. The most active hydrogenation sites are selected and it is found that the most stable hydrogenation sites are Houts1 and Houts3 for fullerenes and endohedral Ti-doped fullerenes, respectively.