Figure 3: The potential energy surface (kcal/mol) of the insertion reaction of Li+ into Ti-T8 with the structures of the exohedral complex (Exo-1), the transition state (TS), and endohedral complex (Endo-2) at the B3LYP/6-311+G(d)+ZPC and HF/6-311+G(d)+ZPC (in parentheses) levels. For the transition state, the side view is in the left quadrangle while the top view is in the right one.