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Canonical and DLPNO-Based G4(MP2)XK-Inspired Composite Wave Function Methods Parametrized against Large and Chemically Diverse Training Sets: Are They More Accurate and/or Robust than Double-Hybrid DFT?
Journal of Chemical Theory and Computation ( IF 5.7 ) Pub Date : 2020-05-26 , DOI: 10.1021/acs.jctc.0c00189
Emmanouil Semidalas 1 , Jan M L Martin 1
Affiliation  

The large and chemically diverse GMTKN55 benchmark was used as a training set for parametrizing composite wave function thermochemistry protocols akin to G4(MP2)XK theory (Chan, B.; Karton, A.; Raghavachari, K. J. Chem. Theory Comput. 2019, 15, 4478–4484). On account of their availability for elements H through Rn, Karlsruhe def2 basis sets were employed. Even after reparametrization, the GMTKN55 WTMAD2 (weighted mean absolute deviation, type 2) for G4(MP2)-XK is actually inferior to that of the best rung-4 DFT functional, ωB97M-V. By increasing the basis set for the MP2 part to def2-QZVPPD, we were able to substantially improve performance at modest cost (if an RI-MP2 approximation is made), with WTMAD2 for this G4(MP2)-XK-D method now comparable to the better rung-5 functionals (albeit at greater cost). A three-tier approach with a scaled MP3/def2-TZVPP intermediate step, however, leads to a G4(MP3)-D method that is markedly superior to even the best double hybrids ωB97M(2) and revDSD-PBEP86-D4. Evaluating the CCSD(T) component with a triple-ζ, rather than split-valence, basis set yields only a modest further improvement that is incommensurate with the drastic increase in computational cost. G4(MP3)-D and G4(MP2)-XK-D have about 40% better WTMAD2, at similar or lower computational cost, than their counterparts G4 and G4(MP2), respectively: detailed comparison reveals that the difference lies in larger molecules due to basis set incompleteness error. An E2/{T,Q} extrapolation and a CCSD(T)/def2-TZVP step provided the G4-T method of high accuracy and with just three fitted parameters. Using KS orbitals in MP2 leads to the G4(MP3|KS)-D method, which entirely eliminates the CCSD(T) step and has no steps costlier than scaled MP3; this shows a path forward to further improvements in double-hybrid density functional methods. None of our final selections require an empirical HLC correction; this cuts the number of empirical parameters in half and avoids discontinuities on potential energy surfaces. G4-T-DLPNO, a variant in which post-MP2 corrections are evaluated at the DLPNO-CCSD(T) level, achieves nearly the accuracy of G4-T but is applicable to much larger systems.

中文翻译:

针对大型和化学多样的训练集进行参数化的基于规范和DLPNO的G4(MP2)XK启发式复合波函数方法:它们是否比双混合DFT更准确和/或更稳健?

大型且化学性质多样的GMTKN55基准用作训练集,用于参数化类似于G4(MP2)XK理论的复合波函数热化学规程(Chan,B .; Karton,A .; Raghavachari,K.J.Chem。Theory Comput201915,4478–4484)。由于它们对于元素H到Rn的可用性,因此使用了Karlsruhe def2基集。即使重新参数化后,G4(MP2)-XK的GMTKN55 WTMAD2(加权平均绝对偏差,类型2)实际上也比最好的梯级4 DFT功能ωB97M-V要差。通过将MP2部分的基础设置增加到def2-QZVPPD,我们能够以适度的成本(如果进行了RI-MP2近似)显着提高性能,而现在用于该G4(MP2)-XK-D方法的WTMAD2具有可比性更好的梯级5功能(尽管成本更高)。但是,采用扩展MP3 / def2-TZVPP中间步骤的三层方法会导致G4(MP3)-D方法明显优于最佳的双重混合体ωB97M(2)和revDSD-PBEP86-D4。用三重ζ而不是分裂价评估CCSD(T)分量,基本集仅产生适度的进一步改进,这与计算成本的急剧增加是不相称的。与相似的G4和G4(MP2)相比,G4(MP3)-D和G4(MP2)-XK-D分别具有相似或更低的计算成本,而WTMAD2的性能要好大约40%:详细比较显示,差异在于分子由于基集不完全性错误。E2 / {T,Q}外推法和CCSD(T)/ def2-TZVP步骤提供了高精度的G4-T方法,并且只有三个拟合参数。在MP2中使用KS轨道会导致产生G4(MP3 | KS)-D方法,该方法完全消除了CCSD(T)步骤,并且没有比缩放MP3昂贵的步骤。这显示了进一步改善双杂交密度功能方法的途径。我们的最终选择均不需要经验性HLC校正;这将经验参数的数量减少了一半,并避免了势能表面上的不连续性。G4-T-DLPNO是在DLPNO-CCSD(T)级别评估MP2后校正的一种变体,几乎达到了G4-T的精度,但适用于更大的系统。
更新日期:2020-07-14
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