高等学校化学学报

高等学校化学学报 ›› 1999, Vol. 20 ›› Issue (6): 941.

• 论文 • 上一篇    下一篇

Si2Br6的分子振动光谱的理论研究

徐学军, 薛英, 谢代前, 鄢国森   

  1. 四川大学化学系, 成都 610064
  • 收稿日期:1998-07-02 出版日期:1999-06-24 发布日期:1999-06-24
  • 通讯作者: 谢代前
  • 作者简介:徐学军,男,29岁,博士研究生.
  • 基金资助:

    国家自然科学基金;高等学校博士学科点专项基金

Studies on Vibrational Spectra and Normal Coordinate Analysis of Hexabrominedisilane

XU Xue-Jun, XUE Ying, XIE Dai-Qian, YAN Guo-Sen   

  1. Department of Chemistry, Sichuan University, Chengdu, 610064
  • Received:1998-07-02 Online:1999-06-24 Published:1999-06-24

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摘要： 用量化从头算方法(HF/6-31G*)和密度泛函方法(B3LYP/6-31G*)以6-31G标准基组加一个极化函数,对Si2Br6分子的平衡几何构型和振动频率分别进行优化和计算,优化的结果与实验结果吻合得较好.按照Pulay的建议对HF/6-31G*水平上所计算的谐性力场进行标度(标度因子取0.9).用HF/6-31G*SQM力场所计算的基频预测值和实验值的平均误差为9.4cm-1,最大误差为23.6cm-1;用B3LYP/6-31G*未标度力场所计算的基频预测值和实验值的平均误差为8.6cm-1,最大误差为16.6cm-1;用该密度泛函方法所计算的基频预测值比用HF/6-31G*的标度后的SQM力场所计算的基频预测值和实验值(除Si-Si键扭转振动基频之外的11条振动基频)吻合得更好.HF/6-31G*和B3LYP/6-31G*计算给出Si-Si键扭转振动基频的预测值分别为14cm-1和9cm-1.

关键词: 从头算, 六溴乙硅烷, DFT方法, 振动基频, 简正坐标分析

Abstract: The optimized geometries, infrared intensities, Raman activities and fundamental vibrational frequencies and PEDs are reported for D3dsymmetry of Si2Br6utilizing HF/6-31G*and B3LYP/6-31G*method. The predicted value of Si-Si torsional vibrational frequency is given. Anormal coordinate analysis has been carried out and HF force field is scaled with scale factor of 0.9 pertinent to all vibrational modes. The average error between the predicted frequencies obtained from HF/6-31G*SQM force field and the observed fundamental vibrational frequencies is 9.4cm-1; the average error between the predicted value from unrefined DFTforce field and the observed result is 8. 6cm-1. The fundamental vibrational frequencies obtained from DFT alculation with B3LYP/6-1G*are in good agreement with the experimental results.

Key words: Ab initio calculation, Hexabrominedisilane, DFT method, Fundamental vibrational frequency, Normal coordinate analysis

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