轨道定域化中π轨道的自动识别  

The Auto-identification of the π-Orbitals in the Program of the Orbital Localization

作　　者：宣正乾[1] 王桐信[1] 虞海敏 虞忠衡[1] 

机构地区：[1]中国科学院化学研究所分子动态与稳态国家重点实验室,北京100080

出　　处：《化学通报》2000年第7期21-24,共4页Chemistry

基　　金：国家自然科学基金! ( 2 9872 0 4 2 );中国科学院化学研究所所长基金

摘　　要：π轨道的自动识别是片断轨道定域化的前提。本文介绍并比较了在程序中几种有效的识别方法—— s原子轨道系数法、p原子轨道系数法、混合识别法 ,综合了它们各自的特点和使用范围 ,使计算机能自动识别各类片断分子中的 π轨道。Automatically identifying of π MOs is a prerequisite to the Kost's localization procedure.There are two methods of the identification.These two methods are based on the coefficients of the s type atomic orbitals and on normal vector of a molecular plane, respectively.The first one is applicable to the most of the conjugated molecules.But,it is not suitable for the five membered ring aromatic compound such as imidazole because > N H fragment has two open shell molecular orbitals both of which look like the π type orbitals.So the second method is necessary to resolve the problem.However,the second one is available to the mono and condensed conjugated system,and it fails to run in the case of the ketenimine like molecules owing to the three π systems(>C=C=N<)which are perpendicular to each other.The “third method”is derived from blending the merits of above mentioned two methods,so that the localization program becomes more effective and compatible.\;

关 键 词：PMO法 π轨道 轨道定域化 自动识别 计算机 

分 类 号：O641[理学—物理化学]