The use of two low‐cost methods for the prediction of the inner‐shells contribution to the correlation energy is analyzed. The Spin‐Component‐Scaled second‐order Møller–Plesset perturbation theory (SCS‐MP2) was reparameterized for the prediction of such contributions. The best results are found when only the same spin term is considered (SSS‐MP2). The Coupled Electron Pair Approximation (CEPA) using the Domain‐based Local Pair Natural Orbital approximation (DLPNO) was also studied for the same purpose. The methods were tested for atomization energies on the W4‐11 test set using basis sets up to quadruple zeta quality. The SSS‐MP2 proved to be a marked improvement upon MP2 decreasing the root‐mean‐square‐error (RMSE) from 0.443 to 0.302 kcal mol−1. The RMSE of DLPNO‐CEPA/1 in the test set is only 0.147 kcal mol−1 and its computational cost is very low considering the intended applications. Furthermore, a linear combination of both methods decreased the RMSE to 0.118 kcal mol−1.

中文翻译：

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通过 DLPNO-CEPA/1 和标度同自旋二阶 Møller-Plesset 扰动理论计算内壳对相关能的贡献

分析了使用两种低成本方法预测内壳对相关能量的贡献。自旋分量缩放二阶 Møller-Plesset 微扰理论 (SCS-MP2) 被重新参数化以预测此类贡献。当只考虑相同的自旋项（SSS-MP2）时，会发现最好的结果。出于相同目的，还研究了使用基于域的局部对自然轨道近似 (DLPNO) 的耦合电子对近似 (CEPA)。这些方法在 W4-11 测试集上使用四倍 zeta 质量的基组测试了原子化能量。SSS-MP2 被证明是对 MP2 的显着改进，将均方根误差 (RMSE) 从 0.443 降低到 0.302 kcal mol-1。测试集中 DLPNO-CEPA/1 的 RMSE 仅为 0。考虑到预期的应用，147 kcal mol−1 及其计算成本非常低。此外，两种方法的线性组合将 RMSE 降低到 0.118 kcal mol-1。