Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, D-45470 Mülheim an der Ruhr, Germany.
J Chem Theory Comput. 2021 Jun 8;17(6):3348-3359. doi: 10.1021/acs.jctc.1c00005. Epub 2021 May 26.
Herein, we introduce a fragment-based local coupled cluster embedding approach for the accurate quantification and analysis of noncovalent interactions in molecular aggregates. Our scheme combines two different expansions of the domain-based local pair natural orbital coupled cluster (DLPNO-CCSD(T)) energy: the many-body expansion (MBE) and the local energy decomposition (LED). The low-order terms in the MBE are initially computed in the presence of an environment that is treated at a low level of theory. Then, LED is used to decompose the energy of each term in the embedded MBE into additive fragment and fragment-pairwise contributions. This information is used to quantify the total energy of the system while providing at the same time in-depth insights into the nature and cooperativity of noncovalent interactions. Two different approaches are introduced and tested, in which the environment is treated at different levels of theory: the local coupled cluster in the Hartree-Fock (LCC-in-HF) method, in which the environment is treated at the HF level; and the electrostatically embedded local coupled cluster method (LCC-in-EE), in which the environment is replaced by point charges. Both schemes are designed to preserve as much as possible the accuracy of the parent local coupled cluster method for total energies, while being embarrassingly parallel and less memory intensive. These schemes appear to be particularly promising for the study of large and complex molecular aggregates at the coupled cluster level, such as condensed phase systems and protein-ligand interactions.
在此，我们介绍了一种基于片段的局域耦合簇嵌入方法，用于准确量化和分析分子聚集体中的非共价相互作用。我们的方案结合了两种不同的基于域的局域对自然轨道耦合簇（DLPNO-CCSD(T)）能量展开：多体展开（MBE）和局域能量分解（LED）。MBE 的低阶项最初是在环境存在的情况下计算的，而环境则以较低的理论水平处理。然后，使用 LED 将嵌入 MBE 中每个项的能量分解为加和片段和片段对贡献。该信息用于量化系统的总能量，同时深入了解非共价相互作用的性质和协同作用。引入并测试了两种不同的方法，其中环境在不同的理论水平下进行处理：哈特ree-Fock（LCC-in-HF）方法中的局域耦合簇，其中环境在 HF 水平下进行处理；以及静电嵌入局域耦合簇方法（LCC-in-EE），其中环境被点电荷取代。这两种方案旨在尽可能保持母体局域耦合簇方法对总能量的准确性，同时具有尴尬并行性和较少的内存占用。这些方案似乎特别有前途用于在耦合簇水平上研究大型和复杂的分子聚集体，例如凝聚相体系和蛋白质-配体相互作用。
