Strain-induced bond localization model

Let us return to Siegel-cyclohexatriene (30) and inspect the relationship between the geometries of the ground state and the twin excited states. The model in Figure 11a (also eq 11) predicts that an attractive 77-curve, displaced to the left of the a-minimum, will reduce the bond alternation induced by the er-strain. Since the 77-curve of the twin excited state is attractive, this state will lose the bond alternation of the ground state and the benzene nucleus will regain its local D%h symmetry. 

---