Bond lengths, reactivities, and aromaticities of benzenoid hydrocarbons based on the valence bond calculations

The Lanczos method, valence bond models were used to analyze the valence bond for pi-electronic systems of benzenoid hydrocarbons. The exact valence bond ground-state wave functions were obtained for benzenoid hydrocarbons of up to 20 pi centers. Site energy, relative local hexagon energy, orientation of electrophilic aromatic substitution and local aromaticities for benzenoid hydrocarbons are discussed.