The role of delocalization in benzene

The influence of 1t delocalization on the geometry of; benzene is examined at.the ab initio SCF level of theory.We find that benzene favors a bond alternating geometry when its canonical1t MOs are replaced by three localized ethylenic orbitals, revealing that delocalization is in part responsible for the equilibrium symmetric structure.In apparent contrast, a cr-1t energy partitioning analysis suggests that the benzene cr framework is responsible for the symmetric structure, the 1t system preferring a distorted geometry.Shai.k, et al. have therefore concluded that delocalization in not an important symmetrizing force in this molecule.We show, however, that the 1t energy component contains a sizable and strongly goometry dependent contribution from the localized (Kekule) wavefunction.Thus, it appears to be misleading to judge the nature of delocalization based on a