Exploring the Mechanism of Reactions of SiX3 and CX3 Radicals with Si20X20 Fullerenes (X = H, F): A Density Functional Study

We have applied density functional calculations to study reactions SiX3 + Si20X20, and CX3 + Si20X20 (X = H, F) based on two reaction channels (H- or F-abstraction and H-or F-displacement from Si20H20 and Si20F20). Our results show that SiX3 radicals prefer the hydrogen or halogen atom abstraction from Si20H20 and Si20F20 fullerenes. The exothermic reaction channels are proceed via reactant-like transition states i.e. the elongation of the breaking bonds of transition states is smaller than that of their forming bonds. Among the mentioned reaction channels, the reactions of SiF3 radical with Si20F20 and CF3 radical with Si20H20 are most favorable both thermodynamically and kinetically with the lowest barrier height exothermic character. Generally, the reactions of Si20H20 and Si20F20 with SiF3 radical are more favorable than SiH3 radical and the reaction of CH3 and CF3 radicals with Si20H20 fullerenes is more favorable than SiH3 and SiF3 radicals. These results are in agreement with the electrostatic surface potentials of reactants.