Accurate configuration interaction calculations of the hyperfine interactions in the benzene cation

The Jahn–Teller distorted states 2B2g and 2B1g of the benzene cation have been studied at the ab initio CI level. Relative energies indicate that the 2B2g state is more stable (the ground state), and the calculated isotropic and anisotropic hyperfine coupling constants for the 2B2g state are in good agreement with the values observed at 4.2K.