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化学学报
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化学学报 ›› 2005, Vol. 63 ›› Issue (24): 2229-2237. 上一篇    下一篇

研究论文

dSH扭曲程序的建立以及在两种基组(NBO, LFMO)下对扭曲分子的能量分解

刘向文，包鹏，宣正乾，虞忠衡*   

  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)
  • 投稿日期:2005-03-28 修回日期:2005-08-31 发布日期:2005-12-28
  • 通讯作者: 虞忠衡

Analysis of Molecular Distortion over the NBO andLFMO Basis Sets with the Automatic dSH Program

LIU Xiang-Wen, BAO Peng, XUAN Zheng-Qian, YU Zhong-Heng*   

  1. (State Key Laboratory of Stable and Unstable Species, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100080)
  • Received:2005-03-28 Revised:2005-08-31 Published:2005-12-28
  • Contact: YU Zhong-Heng*

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介绍了dSH 扭曲法产生的背景, 为dSH扭曲法研究Mills-Nixon效应提供了一个自动化程序和方法. 通过在程序中引入随机函数模拟并代替了人工调节构型参数的过程, 提高了效率并拓宽了程序的应用范围. 利用此程序算得三元苯并分子C6B3H3 和C6O3的一系列的扭曲结构, 并利用自然键轨道(NBO)和定域片断分子轨道(LFMO)两种基组分别进行了NBO能量分析和Morokuma SCF能量分解, 并以动态的方式分析了扭曲过程中垂直共振能及其各分量的变化趋势, 比较了不同基组和不同分析方法下的扭曲的驱动力和阻力. 由分析知, 由于NBO基组的非绝对定域性和NBO能量分析方法的一次性对角化直接导致NBO基组及其能量分析方法在dSH扭曲能量分析中的不合理.

关键词: dSH 扭曲, 随机函数, NBO, LFMO, 垂直共振能

An automatic program to form the dSH geometry of a molecule was developed. The program was based on the random function, and various dSH geometries of each of the two molecules C6B3H3 and C6O3 were obtained from the program. Then the NBO energetic analysis and Morokuma SCF energy partition were performed, over the NBO and LFMO basis sets respectively, for each of these geometries, and these two energy partitions could provide any specific dSH geometry with the different values of the vertical resonance energy (VRE). At the same time, the driving force and resistant force for distorted molecules, obtained from the two different energy partitions over the NBO and LFMO basis sets, were compared. As a result, it is clear that the energy analysis results not only depend on the basis set but also on the analysis method. Furthermore, the results obtained from the NBO basis set and the NBO energetic analysis seem to be unsound.

Key words: dSH distortion, random function, natural bond orbital, localized fragment molecular orbital (LFMO), vertical resonance energy