Department of Chemical and Environmental Engineering and Department of Mathematics, University of California , Riverside, California 92521, United States.
Langmuir. 2013 Oct 22;29(42):12997-3002. doi: 10.1021/la403082q. Epub 2013 Oct 10.
We present an efficient computational procedure for the rapid prediction of the self-diffusivity of gas molecules in nanoporous materials by a combination of the Knudsen model, Rosenfeld's excess-entropy scaling method, and a classical density functional theory (DFT). The self-diffusivity conforms to the Knudsen model at low density, and the effects of intermolecular interactions at higher densities are accounted for by Rosenfeld's excess-entropy scaling method. The classical DFT provides a convenient way to calculate the excess entropy used in the scaling analysis. The hybrid computational procedure has been calibrated with MD simulation for the adsorption of H2, He, Ne, and Ar gases in several nanoporous materials over a broad range of pressure. It predicts adsorption isotherms and different types of diffusion behavior in excellent agreement with the simulation results. Although the simulation of gas diffusion in nanoporous materials is extremely time-consuming, the new procedure is computationally very efficient because it uses only single molecular and thermodynamic parameters.
我们提出了一种高效的计算程序，通过组合克努森模型、罗森菲尔德过剩熵标度方法和经典密度泛函理论（DFT），快速预测气体分子在纳米多孔材料中的自扩散率。自扩散率在低密度下符合克努森模型，而在较高密度下的分子间相互作用的影响则由罗森菲尔德过剩熵标度方法来考虑。经典的 DFT 为在标度分析中使用的过剩熵提供了一种方便的计算方法。该混合计算程序已经通过 MD 模拟对 H2、He、Ne 和 Ar 气体在几种纳米多孔材料中的吸附进行了校准，涵盖了广泛的压力范围。它预测的吸附等温线和不同类型的扩散行为与模拟结果非常吻合。尽管纳米多孔材料中气体扩散的模拟非常耗时，但由于新程序仅使用单一的分子和热力学参数，因此在计算上非常高效。
