Mutual influence of molecular diffusion in gas and surface phases
Mutual influence of molecular diffusion in gas and surface phases
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DOI：
10.1103/physreve.97.013101
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发表时间：
2018-01-03
影响因子：
2.4
通讯作者：
Kinefuchi, Ikuya
中科院分区：
文献类型：
--
作者：
Hori, Takuma;Kamino, Takafumi;Kinefuchi, Ikuya
我们开发了同时处理气相和表面相扩散的分子输运模拟方法，以确定表面扩散对总体扩散系数的影响。表面扩散现象被纳入测试粒子法和均方位移法中，这些方法通常仅用于气相传输。结果发现，对于简单的圆柱孔，两种方法计算的存在表面扩散的扩散系数表现出良好的一致性。我们还确认这两种方法都能重现解析解。然后，使用所开发的方法计算墨瓶状孔的扩散系数。我们的结果表明，表面扩散有助于气相中的分子传输。此外，已知由物理结构唯一确定的表面弯曲系数受到气相扩散的影响。气相扩散和表面扩散的相互影响表明，为了准确评估扩散系数，必须同时计算它们。
We develop molecular transport simulation methods that simultaneously deal with gas- and surface-phase diffusions to determine the effect of surface diffusion on the overall diffusion coefficients. The phenomenon of surface diffusion is incorporated into the test particle method and the mean square displacement method, which are typically employed only for gas- phase transport. It is found that for a simple cylindrical pore, the diffusion coefficients in the presence of surface diffusion calculated by these two methods show good agreement. We also confirm that bothmethods reproduce the analytical solution. Then, the diffusion coefficients for ink-bottle-shaped pores are calculated using the developed method. Our results show that surface diffusion assists molecular transport in the gas phase. Moreover, the surface tortuosity factor, which is known to be uniquely determined by physical structure, is influenced by the presence of gas- phase diffusion. This mutual influence of gas- phase diffusion and surface diffusion indicates that their simultaneous calculation is necessary for an accurate evaluation of the diffusion coefficients.