On the Inclusion of Post-MP2 Contributions to Double-Hybrid Density Functionals
On the Inclusion of Post-MP2 Contributions to Double-Hybrid Density Functionals
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DOI：
10.1002/jcc.23972
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发表时间：
2016-01-15
影响因子：
3
通讯作者：
Radom, Leo
中科院分区：
文献类型：
--
作者：
Chan, Bun;Goerigk, Lars;Radom, Leo
在这项研究中，我们探讨了用后二阶Moller-Plesset-type理论(MP2)关联项补充Dut自旋分量尺度双杂化密度泛函方法的效果。我们发现，加入额外的MP3关联能量对性能几乎没有影响。来自MP4的相关效应的进一步添加通常会导致性能的小幅改进。然而，我们发现，对于更具挑战性的系统，高阶微扰相关效应的加入并没有纠正DUT的一些主要缺陷，而MP4的使用实际上在某些情况下导致了性能的显著恶化。我们还发现，使用CCSD(T)的关联能量而不是MP3和MP4的关联能量并没有导致比基于MP4的方法有实质性的改进，无论是在一般情况下，还是在我们所研究的一些困难的情况下。另一个观察结果是，对于以非共价相互作用为主的大系统，DUT和两个基于MPN的后MP2双杂化密度泛函理论(DFT)过程都受益于色散校正的加入。总体而言，我们的调查表明，当前一代基于MP2的双混合DFT方法可能已经提供了接近与自旋分量缩放相结合的双混合方法所能达到的最佳性能。开发更好的双杂交是一个活跃的研究领域，我们希望我们的研究能提供有价值的见解。我们建议继续使用现有的基于MP2的双杂交方法，作为混合密度函数程序和基于高级波函数的程序之间的桥梁。(C)2015年威利期刊公司。
In this study, we explore the effect of supplementing the DuT spin-component-scaled double-hybrid density functional method with post-second-order Moller-Plesset-type theory (MP2) correlation terms. We find that the inclusion of additional MP3 correlation energies has almost no effect on the performance. Further addition of correlation effects from MP4 generally leads to a small improvement in the performance. However, we find that the inclusion of the higher-order perturbative correlation effects does not rectify some major shortcomings of DuT for more challenging systems, and the use of MP4, in fact, leads to a significant deterioration in the performance in some cases. We also find that the use of correlation energies from CCSD(T) instead of those from MP3 and MP4 does not lead to a substantial improvement over the MP4-based method, both in general and in some difficult cases that we have examined. An additional observation is that, for large systems that are dominated by noncovalent interactions, DuT and the two MPn-based post-MP2 double-hybrid density functional theory (DFT) procedures all benefit from the inclusion of dispersion corrections. Overall, our investigation suggests that the current generation of MP2-based double-hybrid DFT methods may already be providing close to the optimal performance that can be achieved with the double-hybrid methodology paired with spin-component-scaling. Development of even better double hybrids is an active research field, and we hope that our study provides valuable insights. We recommend the continuing use of existing MP2-based double-hybrid methods as a bridging level between hybrid density functional procedures and high-level wave-function-based procedures. (C) 2015 Wiley Periodicals, Inc.