Bifurcation of potential energy surfaces(PES) along the reaction paths (RPS) has stimu-lated great interest of some chemists. It was first discovered by Dewar et al. intheir study on the decyclization of cyclobutene, and that the Wood-Hoffmann rule lost its Bifurcation of potential energy surfaces (PES) along the reaction paths (RPS) has stimu-lated great interest of some chemists. It was first discovered by Dewar et al. Intheir study on the decyclization of cyclobutene, and that the Wood-Hoffmann rule lost its