Dynamic Monte-Carlo and mean-field study of the effect of strong adsorption sites on self-diffusion in zeolites
Dynamic Monte-Carlo and mean-field study of the effect of strong adsorption sites on self-diffusion in zeolites
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DOI：
10.1016/s0009-2509(98)00473-4
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发表时间：
1999-08-01
影响因子：
4.7
通讯作者：
Chakraborty, AK
中科院分区：
文献类型：
--
作者：
Coppens, MO;Bell, AT;Chakraborty, AK
本文采用简单的平均场理论和动态蒙特-卡罗模拟方法，对分子筛中的自扩散进行了研究。我们的方法是强大的，因为它的简单性，灵活性和能力来研究各种因素的影响：孔隙网络的拓扑结构，强吸附位点的分数，弱和强的网站的相对强度，每个沸石笼的网站的数量，和内到外跳跃概率的比率。尽管建模简单，我们的结果证实了在脉冲保持梯度NMR实验中观察到的定性趋势，并能够解释它们。对于ZSM-5，我们还发现了一种新的可能类型的功能依赖性的扩散率占用，有两个倾斜点。(C)1999 Elsevier Science Ltd.保留所有权利。
Self-diffusion in zeolites is studied using a simple mean-field theory and dynamic Monte-Carlo simulations of diffusion on a lattice model of the zeolite pore space. Our method is powerful, because of its simplicity, flexibility and ability to study the influence of various factors: the topology of the pore network, the fraction of strong adsorption sites, the relative strengths of weak and strong sites, the number of sites per zeolite cage, and the ratio of intracage to extracage hopping probabilities. Notwithstanding the simplicity of the modeling, our results confirm the qualitative trends observed in pulsed-held gradient NMR experiments, and are able to explain them. For ZSM-5, we also found a new possible type of functional dependency of the diffusivity on occupancy, with two inclination points. (C) 1999 Elsevier Science Ltd. All rights reserved.