Lomba Enrique, Bores Cecilia, Notario Rafael, Sánchez-Gil V
Instituto de Química Física Rocasolano, CSIC, Calle Serrano 119, E-28026 Madrid, Spain.
J Phys Condens Matter. 2016 Sep 1;28(34):344006. doi: 10.1088/0953-8984/28/34/344006. Epub 2016 Jul 1.
In this work we have assessed the ability of a recently proposed three-dimensional integral equation approach to describe the explicit spatial distribution of molecular hydrogen confined in a crystal formed by short-capped nanotubes of C50 H10. To that aim we have resorted to extensive molecular simulation calculations whose results have been compared with our three-dimensional integral equation approximation. We have first tested the ability of a single C50 H10 nanocage for the encapsulation of H2 by means of molecular dynamics simulations, in particular using targeted molecular dynamics to estimate the binding Gibbs energy of a host hydrogen molecule inside the nanocage. Then, we have investigated the adsorption isotherm of the nanocage crystal using grand canonical Monte Carlo simulations in order to evaluate the maximum load of molecular hydrogen. For a packing close to the maximum load explicit hydrogen density maps and density profiles have been determined using molecular dynamics simulations and the three-dimensional Ornstein-Zernike equation with a hypernetted chain closure. In these conditions of extremely tight confinement the theoretical approach has shown to be able to reproduce the three-dimensional structure of the adsorbed fluid with accuracy down to the finest details.
在这项工作中，我们评估了最近提出的一种三维积分方程方法描述C50 H10短封端纳米管形成的晶体中受限分子氢的明确空间分布的能力。为此，我们采用了广泛的分子模拟计算，并将其结果与我们的三维积分方程近似进行了比较。我们首先通过分子动力学模拟，特别是使用靶向分子动力学来估计纳米笼内宿主氢分子的结合吉布斯自由能，测试了单个C50 H10纳米笼封装H2的能力。然后，我们使用巨正则蒙特卡罗模拟研究了纳米笼晶体的吸附等温线，以评估分子氢的最大负载量。对于接近最大负载量的堆积，使用分子动力学模拟和带有超网链闭合的三维奥恩斯坦-泽尔尼克方程确定了明确的氢密度图和密度分布。在这种极度紧密受限的条件下，理论方法已证明能够精确再现吸附流体的三维结构，直至最细微的细节。
