Third-Order Møller–Plesset Theory Made More Useful? The Role of Density Functional Theory Orbitals

The
practical utility of Møller–Plesset (MP) perturbation
theory is severely constrained by the use of Hartree–Fock (HF)
orbitals. It has recently been shown that the use of regularized orbital-optimized
MP2 orbitals and scaling of MP3 energy could lead to a significant
reduction in MP3 error [Bertels, L. W.; J. Phys. Chem. Lett. 2019, 10, 4170 4176]. In this work, we examine whether density
functional theory (DFT)-optimized orbitals can be similarly employed
to improve the performance of MP theory at both the MP2 and MP3 levels.
We find that the use of DFT orbitals leads to significantly improved
performance for prediction of thermochemistry, barrier heights, noncovalent
interactions, and dipole moments relative to the standard HF-based
MP theory. Indeed, MP3 (with or without scaling) with DFT orbitals
is found to surpass the accuracy of coupled-cluster singles and doubles
(CCSD) for several data sets. We also found that the results are not
particularly functional sensitive in most cases (although range-separated
hybrid functionals with low delocalization error perform the best).
MP3 based on DFT orbitals thus appears to be an efficient, noniterative O(N6) scaling wave-function
approach for single-reference electronic structure computations. Scaled
MP2 with DFT orbitals is also found to be quite accurate in many cases,
although modern double hybrid functionals are likely to be considerably
more accurate.

莫勒-普莱斯脱（Møller–Plesset，简称MP）微扰理论的实用价值受到哈特里-福克（Hartree–Fock，简称HF）轨道应用的严格限制。近期研究表明，采用正则化的轨道优化MP2轨道以及MP3能量的缩放处理，可显著降低MP3误差[参见Bertels, L. W. 与J. Phys. Chem. Lett. 2019, 10, 4170-4176]。在本研究中，我们探讨密度泛函理论（Density Functional Theory，简称DFT）优化的轨道是否可以类似地应用于提升MP理论在MP2和MP3层面的性能。我们发现，采用DFT轨道能够显著提升对热化学、能垒高度、非共价相互作用和偶极矩的预测性能，相较于基于标准的HF轨道的MP理论而言。实际上，使用DFT轨道的MP3（无论是否缩放）在多个数据集中被发现其精度超越了耦合簇单双占据（Coupled-Cluster Singles and Doubles，简称CCSD）的计算精度。此外，我们还发现，在大多数情况下，结果对函数的选择并不特别敏感（尽管范围分隔混合泛函在低去局域化误差方面表现最佳）。因此，基于DFT轨道的MP3似乎成为了一种高效、非迭代、O(N6)缩放标度的波函数方法，适用于单参考电子结构计算。采用DFT轨道的正则化MP2在许多情况下也显示出相当高的精度，尽管现代双杂化泛函可能具有更高的精度。