Theoretical study of the benzene cation

The Jahn-Teller distorted states, B-2(2g) and B-2(1g) of the benzene radica l cation have been studied by using ah initio MPn and SDCI methods. The cal culations indicate that B-2(2g), is the ground state of the benzene cation and that B-2(1g), is higher in energy than B-2(2g) and represents a saddle point. The calculated isotropic and anisotropic hyperfine coupling constant s for the B-2(2g) State are in excellent agreement with those obtained from the ESR experiments. It is concluded that the benzene cation is in the B-2 (2g) Jahn-Teller distorted state.