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arXiv 1702.03007cond-mat.mtrl-sci
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氢和水分子对碳纳米材料的粘附力有多强?

How strongly do hydrogen and water molecules stick to carbon nanomaterials?

Yasmine S. Al-Hamdani, Dario Alfè, Angelos Michaelides

摘要:

在许多应用中,分子氢和水与碳纳米材料的相互作用强度与储氢、水处理和水流有关。然而,氢和水与碳纳米管(CNT)的准确相互作用能仍然很少,尽管具有可靠的基准数据来通知实验和验证计算模型的重要性。在这里,基准固定节点扩散蒙特卡罗(DMC)的相互作用能提供氢和水单体,内部和外部一个典型的锯齿形CNT。DMC的相互作用能提供了有价值的洞察分子与碳纳米管的相互作用一般,也预计将特别相关的碳纳米管上的气体吸收研究。此外,选择的密度泛函理论(DFT)交换相关(xc)泛函和力场势,应该是适合这些系统,进行了比较。一个意想不到的变化被发现在DFT范德华(vdW)模型的性能,特别是。不同vdW模型之间的特殊差异的分析表明,中程相关性(约3至5欧姆)在CNT中起着关键作用,并且一些vdW模型预测得很差。使用准确的参考信息,这项工作揭示了xc泛函和力场表现良好的分子与碳纳米管相互作用。这些发现将对未来研究这些和相关系统的工作有价值,这些系统涉及分子与低维系统的相互作用。

英文摘要:

The interaction strength of molecular hydrogen and water to carbon nanomaterials is relevant to, among many applications, hydrogen storage, water treatment, and water flow. However, accurate interaction energies for hydrogen and water with carbon nanotubes(CNTs) remain scarce despite the importance of having reliable benchmark data to inform experiments and to validate computational models. Here, benchmark fixed-node diffusion Monte Carlo (DMC) interaction energies are provided for hydrogen and water monomers, inside and outside a typical zigzag CNT. The DMC interaction energies provide valuable insight into molecular interactions with CNTs in general, and are also expected to be particularly relevant to gas uptake studies on CNTs. In addition, a selection of density functional theory (DFT) exchangecorrelation(xc) functionals and force field potentials that ought to be suitable for these systems, is compared. An unexpected variation is found in the performance of DFT van der Waals (vdW) models in particular. An analysis of the peculiar discrepancy between different vdW models indicates that medium-range correlation (at circa 3 to 5 Å) plays a key role inside CNTs, and is poorly predicted by some vdW models. Using accurate reference information, this work reveals which xc functionals and force fields perform well for molecules interacting with CNTs. The findings will be valuable to future work on these and related systems, that involve molecules interacting with low-dimensional systems.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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