The popular method of calculating the noncovalent interaction energies at the coupled‐cluster single‐, double‐, and perturbative triple‐excitations [CCSD(T)] theory level in the complete basis set (CBS) limit was to add a CCSD(T) correction term to the CBS second‐order Møller‐Plesset perturbation theory (MP2). The CCSD(T) correction term is the difference between the CCSD(T) and MP2 interaction energies evaluated in a medium basis set. However, the CCSD(T) calculations with the medium basis sets are still very expensive for systems with more than 30 atoms. Comparatively, the domain‐based local pair natural orbital coupled‐cluster method [DLPNO‐CCSD(T)] can be applied to large systems with over 1,000 atoms. Considering both the computational accuracy and efficiency, in this work, we propose a new scheme to calculate the CCSD(T)/CBS interaction energies. In this scheme, the MP2/CBS term keeps intact and the CCSD(T) correction term is replaced by a DLPNO‐CCSD(T) correction term which is the difference between the DLPNO‐CCSD(T) and DLPNO‐MP2 interaction energies evaluated in a medium basis set. The interaction energies of the noncovalent systems in the S22, HSG, HBC6, NBC10, and S66 databases were recalculated employing this new scheme. The consistent and tight settings of the truncation parameters for DLPNO‐CCSD(T) and DLPNO‐MP2 in this noncanonical CCSD(T)/CBS calculations lead to the maximum absolute deviation and root‐mean‐square deviation from the canonical CCSD(T)/CBS interaction energies of less than or equal to 0.28 kcal/mol and 0.09 kcal/mol, respectively. The high accuracy and low cost of this new computational scheme make it an excellent candidate for the study of large noncovalent systems.

中文翻译：

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以更低成本但准确的方式计算 CCSD(T)/CBS 非共价相互作用能

在完整基组 (CBS) 限制中计算耦合簇单、双和微扰三激发 [CCSD(T)] 理论水平的非共价相互作用能的流行方法是添加 CCSD(T) CBS 二阶 Møller-Plesset 微扰理论 (MP2) 的修正项。CCSD(T) 校正项是在中等基组中评估的 CCSD(T) 和 MP2 相互作用能之间的差值。然而，对于超过 30 个原子的系统，使用中等基组的 CCSD(T) 计算仍然非常昂贵。相比之下，基于域的局部对自然轨道耦合簇方法 [DLPNO-CCSD(T)] 可应用于具有超过 1,000 个原子的大型系统。考虑到计算精度和效率，在这项工作中，我们提出了一种计算 CCSD(T)/CBS 相互作用能的新方案。在这个方案中，MP2/CBS 项保持不变，CCSD(T) 校正项被 DLPNO-CCSD(T) 校正项取代，这是评估的 DLPNO-CCSD(T) 和 DLPNO-MP2 相互作用能之间的差异在中等基组中。S22、HSG、HBC6、NBC10 和 S66 数据库中非共价系统的相互作用能使用这种新方案重新计算。在此非规范 CCSD(T)/CBS 计算中，DLPNO-CCSD(T) 和 DLPNO-MP2 截断参数的一致和严格设置导致与规范 CCSD(T) 的最大绝对偏差和均方根偏差/CBS 相互作用能分别小于或等于 0.28 kcal/mol 和 0.09 kcal/mol。