Funding information XSEDE, Grant/Award Number: CHE170081; National Science Foundation, Grant/Award Number: CHE-1665336 Abstract We present a graph-theoretic approach to adaptively compute many-body approximations in an efficient manner to perform (a) accurate post-Hartree–Fock (HF) ab initio molecular dynamics (AIMD) at density functional theory (DFT) cost for mediumto large-sized molecular clusters, (b) hybrid DFT electronic structure calculations for condensed-phase simulations at the cost of pure density functionals, (c) reduced-cost on-the-fly basis extrapolation for gas-phase AIMD and condensed phase studies, and (d) accurate post-HF-level potential energy surfaces at DFT cost for quantum nuclear effects. The salient features of our approach are ONIOM-like in that (a) the full system (cluster or condensed phase) calculation is performed at a lower level of theory (pure DFT for condensed phase or hybrid DFT for molecular systems), and (b) this approximation is improved through a correction term that captures all many-body interactions up to any given order within a higher level of theory (hybrid DFT for condensed phase; CCSD or MP2 for cluster), combined through graph-theoretic methods. Specifically, a region of chemical interest is coarse-grained into a set of nodes and these nodes are then connected to form edges based on a given definition of local envelope (or threshold) of interactions. The nodes and edges together define a graph, which forms the basis for developing the many-body expansion. The methods are demonstrated through (a) ab initio dynamics studies on protonated water clusters and polypeptide fragments, (b) potential energy surface calculations on one-dimensional water chains such as those found in ion channels, and (c) conformational stabilization and lattice energy studies on homogeneous and heterogeneous surfaces of water with organic adsorbates using two-dimensional periodic boundary conditions.

中文翻译：

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嵌入式、图形理论定义的 DFT 波函数和 DFT-in-DFT 的多体近似：在气相和凝聚相 ab initio 分子动力学中的应用，以及量子核效应的潜在表面

资金信息 XSEDE，资助/奖励编号：CHE170081；美国国家科学基金会，资助/奖项编号：CHE-1665336 摘要我们提出了一种图论方法，以有效的方式自适应地计算多体近似值，以执行 (a) 准确的后 Hartree-Fock (HF) ab initio 分子动力学（ AIMD) 以密度泛函理论 (DFT) 为中到大型分子簇的成本，(b) 以纯密度泛函为代价的凝聚相模拟的混合 DFT 电子结构计算，(c) 即时降低成本用于气相 AIMD 和凝聚相研究的基础外推，以及 (d) 以 DFT 为代价的精确后 HF 级势能面，用于量子核效应。我们的方法的显着特征类似于 ONIOM，因为 (a) 整个系统（簇或凝聚相）计算是在较低的理论水平（凝聚相的纯 DFT 或分子系统的混合 DFT）进行的，和 (b ) 这种近似通过一个校正项得到改进，该校正项在更高的理论水平（凝聚相的混合 DFT；簇的 CCSD 或 MP2）中捕获所有多体相互作用，直到任何给定的阶数，并通过图论方法组合。具体而言，将感兴趣的化学区域粗粒度化为一组节点，然后将这些节点连接起来，根据给定的相互作用的局部包络（或阈值）定义形成边。节点和边一起定义了一个图，它构成了开发多体扩展的基础。