Although sometimes derided as “weak” interactions, non-covalent forces play a critical role in ligand binding and crystal packing and in determining the conformational landscape of flexible molecules. Symmetry-adapted perturbation theory (SAPT) provides a framework for accurate ab initio calculation of intermolecular interactions and furnishes a natural decomposition of the interaction energy into physically meaningful components: semiclassical electrostatics (rigorously obtained from monomer charge densities), Pauli or steric repulsion, induction (including both polarization and charge transfer), and dispersion. This decomposition helps to foster deeper understanding of non-covalent interactions and can be used to construct transferable, physics-based force fields. Separability of the SAPT interaction energy also provides the flexibility to construct composite methods, a feature that we exploit to improve the description of dispersion interactions. These are challenging to describe accurately because they arise from nonlocal electron correlation effects that appear for the first time at second order in perturbation theory but are not quantitatively described at that level.

中文翻译：

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使用新形式的对称适应微扰理论预测和理解非共价相互作用

尽管有时被嘲笑为“弱”相互作用，但非共价力在配体结合和晶体堆积以及确定柔性分子的构象景观方面起着关键作用。对称适应微扰理论 (SAPT) 为准确的从头计算提供了框架分子间相互作用的计算，并将相互作用能自然分解为具有物理意义的成分：半经典静电（从单体电荷密度严格获得）、泡利或空间排斥、感应（包括极化和电荷转移）和色散。这种分解有助于加深对非共价相互作用的理解，并可用于构建可转移的、基于物理的力场。SAPT 相互作用能的可分离性还提供了构建复合方法的灵活性，我们利用这一特征来改进对色散相互作用的描述。