Department of Chemistry, University of California, Berkeley, California 94720, United States.
Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States.
J Phys Chem Lett. 2021 Dec 23;12(50):12084-12097. doi: 10.1021/acs.jpclett.1c03468. Epub 2021 Dec 15.
Second-order Møller-Plesset theory (MP2) notoriously breaks down for π-driven dispersion interactions and dative bonds in transition metal complexes. Herein, we investigate three physically justified forms of single-parameter, energy-gap dependent regularization which can yield high and transferable accuracy for a variety of noncovalent interactions (including S22, S66, and L7 test sets) and (mostly closed shell) transition metal thermochemistry. Regularization serves to damp overestimated pairwise additive contributions, renormalizing first-order amplitudes such that the effects of higher-order correlations are incorporated. The optimal parameter values for the noncovalent and transition metal sets are 1.1, 0.7, and 0.4 for κ, σ, and σ regularizers, respectively. However, such regularization slightly degrades the accuracy of conventional MP2 for some small-molecule test sets, most of which have relatively large average frontier energy gaps. Our results suggest that appropriately regularized MP2 models may improve double hybrid density functionals, at no additional cost over conventional MP2.
二阶 Møller-Plesset 理论 (MP2) 在处理π 驱动的分散相互作用和过渡金属配合物中的 dative 键时，众所周知会出现问题。在此，我们研究了三种物理合理的单参数、能隙相关正则化形式，它们可以为各种非共价相互作用（包括 S22、S66 和 L7 测试集）和（主要是闭壳层）过渡金属热化学提供高精度和可转移的准确性。正则化用于抑制过高估计的对加贡献，重新调整一阶幅度，从而纳入更高阶相关性的影响。对于非共价和过渡金属数据集，κ、σ 和 σ 正则化器的最佳参数值分别为 1.1、0.7 和 0.4。然而，对于一些平均前线能隙相对较大的小分子测试集，这种正则化略微降低了传统 MP2 的准确性。我们的结果表明，适当正则化的 MP2 模型可能会改善双杂交密度泛函，而不会增加传统 MP2 的额外成本。
