Effect of the Surface Energy Barrier on Sorbate Diffusion in AlPO4-5
Effect of the Surface Energy Barrier on Sorbate Diffusion in AlPO4-5
复制标题
表面能垒对 AlPO4-5 中山梨酸盐扩散的影响
DOI：
10.1021/jp003350g
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发表时间：
2001
影响因子：
3.3
通讯作者：
Hsueh
中科院分区：
文献类型：
--
作者：
G. Arya;E. Maginn;Hsueh
使用两种分子模拟技术的孔出口效应的分子在AlPO 4 -5孔的扩散的重要性进行评估。在第一种方法中，一个双控制体积巨正则分子动力学技术被用来获得甲烷的截断晶体作为温度和吸附负载的函数的分子通量。模拟结果表明，存在一个低温的表面障碍扩散，这阻碍了甲烷相对于其表观通量在材料的晶内区域的流量。随着温度和载荷的增加，这种孔出口屏障趋于减小。提出了一种基于聚类现象的解释来解释后者。接下来，提出了一个简单的活化运输模型来预测的表面势垒的相对重要性，在AlPO 4 -5山梨酸盐的运输。一个吸附分子沿截断晶体孔轴沿着的平均力势提供了所需的活化能势垒.
The importance of pore exit effects on the diffusion of molecules in AlPO4-5 pores is evaluated using two molecular modeling techniques. In the first approach, a dual control volume grand canonical molecular dynamics technique is used to obtain molecular fluxes of methane out of the truncated crystal as a function of temperature and sorbate loading. The simulation results indicate the presence of a low-temperature surface barrier for diffusion, which retards the flux of methane relative to its apparent flux in the intracrystalline regions of the material. This pore exit barrier tends to diminish as temperature and loading increase. An explanation based on clustering phenomena is proposed to explain the latter. Next, a simple activated transport model is proposed to predict the relative importance of the surface barrier on the transport of sorbates in AlPO4-5. The potential of mean force for a single sorbate molecule along the pore axis of a truncated crystal provides the required activation energy barrier...