Benzene Second-order Jahn-Teller

We apply our second-order Ehrenfest method to a model system benzene radical cation. Ionization of the neutral from the degenerate HOMO/HOMO-1 leads to the Jahn-Teller [15] effect in the cation. There is a peaked conical intersection between the two lowest-energy eigenstates Dq and Dy at geometries with D h symmetry. Figure 1 represents the surrounding moat of the conical intersection seen from above. It contains several valence bond (VB) resonance structures three equivalent quinoid structures... 

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