Role of bifurcation in the bond shifting of cyclooctatetraene.

The present study of the cyclooctatetraene potential energy surface shows the presence of a bifurcation (valley ridge inflection point) in the intrinsic reaction coordinate path between the two transition states of D(8h) and D(4h) symmetries. This result is of capital importance for the correct understanding of the bond shifting and ring inversion processes in this compound.