高等学校化学学报

高等学校化学学报 ›› 2001, Vol. 22 ›› Issue (10): 1715.

• 研究论文 • 上一篇    下一篇

单占据片断轨道的组合式(Kost+Perkin)定域化

虞忠衡, 郭彦伸, 彭晓琦, 宣正乾   

  1. 中国科学院化学研究所分子动态稳态国家重点实验室, 北京 100080
  • 收稿日期:2000-08-02 出版日期:2001-10-24 发布日期:2001-10-24
  • 通讯作者: 虞忠衡(1944年出生),男,博士,研究员,博士生导师,从事物理有机化学研究.E-mail:yuzh@infoc3.icas.ac.cn E-mail:yuzh@infoc.icas.ac.cn
  • 基金资助:

    国家自然科学基金(批准号:29872042;20072041;2003201)资助

Localization of a Combinatorial Procedure for Singly Occupied Fragment FMOs

YU Zhong-Heng, GUO Yan-Shen, PENG Xiao-Qi, XUAN Zheng-Qian   

  1. State Key Laboratory of Stable and Unstable Species, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100080, China
  • Received:2000-08-02 Online:2001-10-24 Published:2001-10-24

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被引次数

2

摘要： 为了使开壳层片断轨道具有正确的集居数,正则轨道必须定域化.但是,在确保目标轨道Φsdan单占据性的同时,Kost定域化也破坏了Φs特定的对称性.实际计算表明,Perkin定域化可以弥补Kost程序的缺陷,将单占据的Φs转化成高度定域的、对称的片断轨道.在片断分子中,C—HR键长r的选择和Kost定域化的方式对Perkin定域化的成败具有重大的影响.当Gaussian基组为STO-3G3-21G和4-31G时,r应为0.1nm;但在6-31G水平下,必须r=0.09nm.

关键词: Kost定域化, Perkin定域化, 片断分子轨道, 片断分子

Abstract: In order to ensure that each of all opened shell-fragment MOs (FMO Φi), obtained from the UHFcomputation for a molecular fragment, has a correct electronic occupancy, the FMOs Φi have to be localized. However, the specified symmetrization of the singly occupied FMOs (Φs) is destroyed while Φs becomes singly occupied after the Kost localization. The Perkin localization, a computational procedure after the Kost localization, transforms Φs into Φs which possesses now the symmetrization which they should have. The way of the Kost localization and setting of the length of the bond C-HRbetween the carbon atom and its referential hydrogen atom HRhave great effects on the symmetric characters of the localized FMOs obtained from the Perkin localzation. In the case of the Gaussian basis sets such as STO-3G, 3-21Gand 4-31G, the bond length r should be set to 0.1 nm, and when6-31Gis used, it should be 0.09 nm.

Key words: The Kost localization, The Perkin localization, Fragment molecular orbital, Fragmental molecule

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