Quantum effects on hydrogen isotope adsorption on single-wall carbon nanohorns.
Quantum effects on hydrogen isotope adsorption on single-wall carbon nanohorns.
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DOI：
10.1021/ja0502573
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发表时间：
2005-04
影响因子：
15
通讯作者：
Hideki Tanaka;H. Kanoh;M. Yudasaka;S. Iijima;K. Kaneko
中科院分区：
文献类型：
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作者：
Hideki Tanaka;H. Kanoh;M. Yudasaka;S. Iijima;K. Kaneko
在 77 K 下测量了单壁碳纳米角 (SWNH) 上的 H(2) 和 D(2) 吸附，并将实验数据与这些氢同位素在模型 SWNH 上吸附的大正则蒙特卡罗模拟进行了比较。通过费曼-希布斯有效势将量子效应纳入模拟中。模拟预测与实验结果吻合良好，表明利用有效势可以成功解释 77 K 下的氢同位素吸附。模拟结果表明，氢同位素优先吸附在势场较强的SWNH锥体部分，量子效应导致SWNH内部吸附的H(2)密度比D(2)小8-26%。 H(2) 和 D(2) 吸附之间的差异随着压力降低而增大，因为 H(2) 的量子扩展比 D(2) 更宽，在 SWNH 模型的狭窄圆锥部分相当有效。这些事实表明，氢吸附的量子效应取决于孔隙结构，即使在 77 K 下也非常重要。
H(2) and D(2) adsorption on single-wall carbon nanohorns (SWNHs) have been measured at 77 K, and the experimental data were compared with grand canonical Monte Carlo simulations for adsorption of these hydrogen isotopes on a model SWNH. Quantum effects were included in the simulations through the Feynman-Hibbs effective potential. The simulation predictions show good agreement with the experimental results and suggest that the hydrogen isotope adsorption at 77 K can be successfully explained with the use of the effective potential. According to the simulations, the hydrogen isotopes are preferentially adsorbed in the cone part of the SWNH with a strong potential field, and quantum effects cause the density of adsorbed H(2) inside the SWNH to be 8-26% smaller than that of D(2). The difference between H(2) and D(2) adsorption increases as pressure decreases because the quantum spreading of H(2), which is wider than that of D(2), is fairly effective at the narrow conical part of the SWNH model. These facts indicate that quantum effects on hydrogen adsorption depend on pore structures and are very important even at 77 K.