Acta Phys. -Chim. Sin. ›› 2008, Vol. 24 ›› Issue (11): 2128-2132.doi: 10.3866/PKU.WHXB20081132

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A Random Walk Model for Molecular Anisotropic Diffusion in Siliceous β-Zeolites

YANG Xiao-Feng; QIN Zhang-Feng; WANG Jian-Guo   

  1. State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan 030001, P. R. China; Department of Physics, North University of China, Taiyuan 030051, P. R. China; Graduate University of the Chinese Academy of Sciences, Beijing 100041, P. R. China
  • Received:2008-07-02 Revised:2008-07-31 Published:2008-11-10
  • Contact: WANG Jian-Guo

Abstract: A model of molecules diffusion in β-zeolite was proposed by assuming that the movement of molecules was a random walk on different adsorption sites. Owing to the topological structures and differences of transition probabilities between adsorption sites through two type of pores, there existed a correlation between diffusion coefficients along two principal axes, which was proved by molecular dynamics simulation of benzene diffusion in β zeolite at different temperatures. The diffusions of argon with different interaction radii showed that the interaction radius was crucial to the fitness of the randomwalk model; the interaction radius must be large enough (near the size of zeolite pores).

Key words: Molecular dynamics, β-zeolite, Diffusion coefficient, Random walk


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