Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, 166 10 Prague, Czech Republic.
Chemphyschem. 2013 Mar 18;14(4):698-707. doi: 10.1002/cphc.201200850. Epub 2013 Jan 11.
The performance of the second-order Møller-Plesset perturbation theory MP2.5 and MP2.X methods, tested on the S22, S66, X40, and other benchmark datasets is briefly reviewed. It is found that both methods produce highly accurate binding energies for the complexes contained in these data sets. Both methods also provide reliable potential energy curves for the complexes in the S66 set. Among the routinely used wavefunction methods, the only other technique that consistently produces lower errors, both for stabilization energies and geometry scans, is the spin-component-scaled coupled-clusters method covering iterative single- and double-electron excitations, which is, however, substantially more computationally intensive. The structures originated from full geometrical gradient optimizations at the MP2.5 and MP2.X level of theory were confirmed to be the closest to the CCSD(T)/CBS (coupled clusters covering iterative single- and double-electron excitations and perturbative triple-electron excitations performed at the complete basis set limit) geometries among all the tested methods (e.g. MP3, SCS(MI)-MP2, MP2, M06-2X, and DFT-D method evaluated with the TPSS functional). The MP2.5 geometries for the tested complexes deviate from the references almost negligibly. Inclusion of the scaled third-order correlation energy results in a substantial improvement of the ability to accurately describe noncovalent interactions. The results shown here serve to support the notion that MP2.5 and MP2.X are reasonable alternative methods for benchmark calculations in cases where system size or (lack of) computational resources preclude the use of CCSD(T)/CBS computations. MP2.X allows for the use of smaller basis sets (i.e. 6-31G*) with results that are nearly identical to those of MP2.5 with larger basis sets, which dramatically decreases computation times and makes calculations on much larger systems possible.
简要回顾了二阶 Møller-Plesset 微扰理论 MP2.5 和 MP2.X 方法在 S22、S66、X40 和其他基准数据集上的性能。结果表明，这两种方法都能为这些数据集所包含的配合物提供高度准确的结合能。这两种方法还为 S66 数据集的配合物提供了可靠的势能曲线。在常用的波函数方法中，唯一一种能在稳定能和几何扫描方面产生更低误差的方法是自旋分量标度的耦合簇方法，该方法涵盖了迭代单电子和双电子激发，然而，它的计算强度要大得多。在 MP2.5 和 MP2.X 理论水平上进行全几何梯度优化得到的结构被证实是所有测试方法中与 CCSD(T)/CBS（耦合簇涵盖迭代单电子和双电子激发以及在完全基组极限下进行的微扰三电子激发）几何形状最接近的结构（例如 MP3、SCS(MI)-MP2、MP2、M06-2X 和用 TPSS 函数评估的 DFT-D 方法）。测试配合物的 MP2.5 几何形状与参考文献几乎没有偏差。包含标度的三阶相关能显著提高准确描述非共价相互作用的能力。这里展示的结果支持了这样一种观点，即当系统大小或（缺乏）计算资源阻止使用 CCSD(T)/CBS 计算时，MP2.5 和 MP2.X 是基准计算的合理替代方法。MP2.X 允许使用更小的基组（即 6-31G*），结果与使用更大基组的 MP2.5 几乎相同，这大大降低了计算时间，使更大系统的计算成为可能。
