Density Functional Theory Study of the Multimode Jahn-Teller Problem in the Fullerene Anion

The fullerene anion, C60 , within the Ih point group, is a spherical molecule subject to the T h Jahn–Teller (JT) distortion. The descent in symmetry goes to the three epikernel subgroups, namely D5d, D3d, and D2h. The last one completely removes the electronic degeneracy, whereas D5d and D3d structures are subject to further JT distortion, leading to C2h minimum energy structure. The multideterminantal density functional theory approach was applied to calculate the JT parameters for all seven different structures of lower symmetry. The multimode problem in this system was addressed using the intrinsic distortion path method, in which the JT distortion is expressed as a linear combination of all totally symmetric normal modes in the particular low symmetry minimum energy conformation. Results obtained by both methods are consistent and give direct insight into the coupling of electronic distribution and nuclear movements in C 60.