论文标题
基于规范和DLPNO的G4（MP2）XK启发的复合波函数方法针对大型和化学多样的训练集进行了参数：它们是否比双重混合DFT更准确和/或健壮？
Canonical and DLPNO-based G4(MP2)XK-inspired composite wavefunction methods parametrized against large and chemically diverse training sets: Are they more accurate and/or robust than double hybrid DFT?
论文作者
论文摘要
大型且化学多样的GMTKN55基准用作类似于G4（MP2）XK理论的参数化复合波函数热化学方案的训练集（Chan等，JCTC 2019，15，4478-4484）。即使在重新训练之后，G4（MP2）-XK的GMTKN55 WTMAD2（加权平均绝对偏差，类型2）实际上不如最好的Rung-4 DFT功能，WB97M-V。通过将MP2零件的基础设置增加到DEF2-QZVPPD，我们能够以适度的成本（如果进行RI-MP2近似）来实质上提高性能，并且该G4（MP2）-XK-D方法现在与较高的Rung-5功能（以更高的成本）相当。然而，具有缩放MP3/DEF2-TZVPP中间步骤的三层方法导致G4（MP3）-D方法显着优于最佳的双杂交WB97M（2）和RevDSD-PBBEP86-D4。评估具有三重率的CCSD（t）组件，而不是分裂价，基本集仅产生一个适度的进一步改进，这与计算成本的急剧增加是不相同的。 G4（MP3）-D和G4（MP2）-XK-D的WTMAD2分别比其对应的G4和G4（MP2）的WTMAD2高约40％：详细的比较表明，由于基础设置的不完整不完全误差，其差异在于较大的分子。 E2/ {T，Q}外推和CCSD（T）/ DEF2-TZVP步骤提供了高精度的G4-T方法，并且仅具有三个拟合参数。在MP2中使用KS轨道会导致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的步骤更昂贵。这显示了一个前进的路径，以进一步改善双杂交密度功能方法。 G4-T-DLPNO是一种在DLPNO-CCSD（T）水平上评估MP2后校正的变体，几乎达到了G4-T的准确性，但适用于更大的系统。
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 et al, JCTC 2019, 15, 4478-4484). 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, wB97M-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 wB97M(2) and revDSD-PBEP86-D4. Evaluating the CCSD(T) component with a triple-zeta, 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. 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.
