Abstract Recently, an intriguing all-carboatomic ring, cyclo[18]carbon, was observed in the condensed phase for the first time, and it quickly attracted widespread attention. In this article, we first investigated the interaction of the cyclo[18]carbon with external environment through electrostatic potential and our recently proposed van der Waals potential, and then examined the strength and nature of the intermolecular interactions between cyclo[18]carbon and various small molecules in detail by state-of-art quantum chemistry calculations and elaborate wavefunction analyses. Finally, we studied the cyclo[18]carbon dimer, which is closely related to actual status of the cyclo[18]carbon in condensed phase. These researches show that the cyclo[18]carbon has a strong tendency to adsorb small molecules to or near its ring center, and the dispersion attraction is found to play a leading role in the binding interaction, while the electrostatic effect has a nonnegligible influence on the configuration of the molecular complexes. Two cyclo[18]carbon molecules can form a relatively stable dimer through prominent π-π stacking effect. Its ideal configuration is found to have a face-to-face D9d symmetry, but this geometry can be easily broken by relative sliding between the two rings due to thermal motion, as revealed by ab initio molecular dynamic simulation.

中文翻译：

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全碳原子环，环[]碳的分子间相互作用特征：专注于分子吸附和堆积

摘要 近年来，首次在凝聚相中观察到了一个有趣的全碳原子环，环[18]碳，并迅速引起了广泛关注。在本文中，我们首先通过静电势和我们最近提出的范德华势研究了环[18]碳与外部环境的相互作用，然后研究了环[18]碳与各种分子间相互作用的强度和性质。通过最先进的量子化学计算和精心设计的波函数分析来详细分析小分子。最后，我们研究了环[18]碳二聚体，它与环[18]碳在凝聚相中的实际状态密切相关。这些研究表明，环[18]碳具有很强的将小分子吸附到其环中心或其附近的倾向，发现分散吸引力在结合相互作用中起主导作用，而静电效应对分子复合物的构型有不可忽视的影响。两个环[18]碳分子通过显着的π-π堆积效应可以形成相对稳定的二聚体。发现其理想配置具有面对面的 D9d 对称性，但正如从头分子动力学模拟所揭示的那样，由于热运动，两个环之间的相对滑动很容易破坏这种几何结构。