定域分子轨道中的σ-π分离

Separation of σ-π Bonds in Localized Molecular Orbitals

对含重键的分子体系,分子轨道定域化会涉及到两种完全不同的重键描述,即等价的重键或“香蕉”键和不等价的σ和π键,文献曾利用杂化轨道法对此进行过讨论。对于定域分子轨道,具体得出哪种描述取决于所采用的定域准则及计算中采用的近似方法。对于从头算法的定域化研究,Boys定域准则强烈地趋向于等价重键描述;Ruedenberg定域准则只是对未共轭的重键体系有较强的等价重键描述倾向,对共轭的重键体系。

A procedure for separating σ and π bonds in the localized molecular orbitals was presented. Combined with ab initio and Boys localization method, the procedure was applied to the investigation of 19 compounds containing multiple bonds. The results of separation of σ and π bonds show that the procedure presented here is a successful and useful one.