物理化学学报 >> 2016, Vol. 32 >> Issue (11): 2709-2716.doi: 10.3866/PKU.WHXB201609132

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分子间相互作用研究的APF-D密度泛函SAM色散校正方法改进

何禹1,2,王一波1,2,*()   

  1. 1 贵州省高性能计算化学重点实验室,贵阳550025
    2 贵州大学网络与信息中心,贵阳550025
  • 收稿日期:2016-07-11 发布日期:2016-11-08
  • 通讯作者: 王一波 E-mail:ybw@gzu.edu.cn
  • 基金资助:
    贵州省自然科学基金(20082116)

An Improvement of the SAM Dispersion Correction in the APF-D Density Functional Method for Studying Intermolecular Interactions

Yu HE1,2,Yi-Bo WANG1,2,*()   

  1. 1 Key Laboratory of High Performance Computational Chemistry, Guiyang 550025, P. R. China
    2 Network and Information Center of Guizhou University, Guiyang 550025, P. R. China
  • Received:2016-07-11 Published:2016-11-08
  • Contact: Yi-Bo WANG E-mail:ybw@gzu.edu.cn
  • Supported by:
    the Natural Science Foundation of Guizhou Province, China(20082116)

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摘要：

APF密度泛函色散校正（APF-D）是由B3PW91和PBE0杂化的APF泛函，加上球形原子模型（SAM）色散校正构成的一种有别于Grimme经验色散校正的密度泛函理论色散校正（DFT-D）方法，计算稀有气体及其与小分子复合物结合能和势能面准确性很高，但对常见氢键、C―H…π和π…π等复合物结合能计算结果明显偏大，在一般性分子间相互作用问题研究中一直未被认可和采纳。我们发现APF-D结合能计算结果偏大的原因是APF泛函与SAM色散校正重复计入了一定量的长程色散能；通过引入不依赖于体系的SAM色散能阻力因子ζ，简单而有效地解决了APF-D色散能过度补偿问题，提出了APF-D改进方案APF-D*；通过S66和L7标准测试集的对照计算表明，APF-D*结合能准确性远高于原始APF-D，达到和超过目前常用的B3LYPD3和ωB97X-D方法水平，并具有较好的计算效率，期待在大体系分子间相互作用研究中得到广泛应用。

关键词: DFT-D, APF泛函, SAM色散校正

Abstract:

Austin-Petersson-Frisch (APF) is a new hybrid density functional method that combines B3PW91 and PBE0. APF-D provides an additional empirical dispersion correction method based on a spherical atom model (SAM), which is different from the Grimme's empirical dispersion correction method. APF-D accurately describes the binding energy and the potential energy surfaces of complexes of noble gas atoms and small hydrocarbon dimers. However, APF-D is not accepted as a standard method to study intermolecular interactions because the results often show a large deviation from the normal range when using the APF-D method to calculate the binding energy of hydrogen bonded complexes, C-H…π and π…π interactions. Our research identified that such a deviation arises from some long-range dispersion that has been double counted by the APF function and the SAM dispersion correction. Therefore, we propose an improved APF-D method, termed APF-D*. By taking advantage of ζ, which is independent of SAM dispersion, we were able to solve effectively the problem of excessive dispersion compensation in APF-D. By comparing the results from S66 and L7 benchmark sets, we find that APF-D* greatly improved the precision of calculations over the traditional APF-D method. The overall accuracy of APF-D* was found to be comparable to or better than current leading DFT methods, such as B3LYP-D3 and ωB97X-D. However, both B3LYP-D3 and ωB97X-D have a much larger computational cost than APF-D*. We believe that APF-D* is a better method to calculate of the intermolecular energy of large molecules.

Key words: DFT-D, APF functional, SAM dispersion correction

MSC2000: 

  • O641