A gradual but steady tide in theoretical chemistry is favoring the exploration of atomic and molecular interactions through the dynamical forces perceived and exerted by the particles of a system. By integrating the quantum mechanical force operator over all the spin and all but one of the spatial coordinates of the electrons, the Ehrenfest force density field reveals these forces directly and is separable into a classical term, related to the electric field, and a quantum mechanical correction, which we introduce and analyze for various atoms and molecules in this work. This exchange-correlation Ehrenfest force density field, Fxc(r), excludes the dominant nuclear components that shape the full Ehrenfest field, revealing information about electron sharing, pairing, and delocalization. In a manner similar, though not equal, to the electron localization function, Fxc(r) unveils covalent and core basins. Its divergence, ∇·Fxc(r), indicates the presence of electron shells in atoms and recovers the positions of lone pairs and the shell structure of ionic, polar, and covalent interactions in molecules. It also exhibits a semiquantitative match with the Laplacian of the electron density that we also explore. In alignment with the established role of exchange-correlation as nature's glue, we demonstrate that a significant number of fundamental concepts in chemical bonding can be derived from the Fxc(r) dynamical field.

中文翻译：

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显示电子定位性的动力学密度场：交换相关 Ehrenfest 力。


理论化学中逐渐但稳定的潮流有利于通过系统粒子感知和施加的动力来探索原子和分子相互作用。通过对电子的所有自旋和除一个空间坐标之外的所有空间坐标进行量子机械力算子的积分，Ehrenfest 力密度场直接揭示了这些力，并且可以分为一个与电场相关的经典术语和一个量子力学校正，我们在这项工作中介绍和分析了各种原子和分子。这个交换相关 Ehrenfest 力密度场 Fxc（r） 排除了塑造整个 Ehrenfest 场的主要核成分，揭示了有关电子共享、配对和离域的信息。Fxc（r） 以类似于电子定位函数的方式，尽管不相等，但它揭示了共价池和核心池。它的背离 ∇·Fxc（r） 表示原子中存在电子壳层，并恢复孤对电子的位置以及分子中离子、极性和共价相互作用的壳层结构。它还表现出与我们同样探索的电子密度的拉普拉斯算子的半定量匹配。与交换相关作为自然界胶水的既定作用相一致，我们证明了化学键中的大量基本概念可以从 Fxc（r） 动力学场中推导出来。