Kekulé-based Valence Bond Model. I. The Ground-state Properties of Conjugated π-Systems  

作　　者：黎书华 马晶 江元生 

出　　处：《Chinese Journal of Chemistry》2002年第11期1168-1179,1125,共13页中国化学（英文版）

基　　金：theNationalNaturalScienceFoundationofChina (No.2 0 0 730 2 0 )

摘　　要：The Kekulé-based valence bond (VB) method, in which the VB model is solved using covalent Kekulé structures as basis functions, is justified in the present work. This method is demonstrated to provide satisfactory descriptions for resonance energies and bond lengths of benzenoid hydrocarbons, being in good agreement with SCF-MO and experimental results. In addition, an alternative way of discussing characters of localized substructures within a polycyclic benzenoid system is suggested based upon such simplified VB calculations. Finally, the symmetries of VB ground states for nonalternant conjugated systems are also illustrated to be obtainable through these calculations, presenting very useful information for understanding the chemical behaviors of some nonalternant conjugated molecules.The Kekulé-based valence bond (VB) method, in which the VB model is solved using covalent Kekulé structures as basis functions, is justified in the present work. This method is demonstrated to provide satisfactory descriptions for resonance energies and bond lengths of benzenoid hydrocarbons, being in good agreement with SCF-MO and experimental results. In addition, an alternative way of discussing characters of localized substructures within a polycyclic benzenoid system is suggested based upon such simplified VB calculations. Finally, the symmetries of VB ground states for nonalternant conjugated systems are also illustrated to be obtainable through these calculations, presenting very useful information for understanding the chemical behaviors of some nonalternant conjugated molecules.

关 键 词：valence bond model Kekulé structures benzenoid hydrocarbons nonalternant conjugated molecules 

分 类 号：O641[理学—物理化学]