Diffusion via space discretization method to study the concentration dependence of self-diffusivity under confinement

作者：Sant Marco; Papadopoulos George K; Theodorou Doros N^*

来源：Journal of Chemical Physics, 2010, 132(13): 134108.

DOI：10.1063/1.3370344

• carbon compounds
• Markov processes
• organic compounds
• self-diffusion
• zeolites

The concentration dependence of self-diffusivity is investigated by means of a novel method, extending our previously developed second-order Markov process model to periodic media. Introducing the concept of minimum-crossing surface, we obtain a unique decomposition of the self-diffusion coefficient into two parameters with specific physical meanings. Two case studies showing a maximum in self-diffusivity as a function of concentration are investigated, along with two cases where such a maximum cannot be present. Subsequently, the method is applied to the large cavity pore network of the ITQ-1 (Mobil tWenty tWo, MWW) zeolite for methane (displaying a maximum in self-diffusivity) and carbon dioxide (no maximum), explaining the diffusivity trend on the basis of the evolution of the model parameters as a function of concentration.

• 出版日期2010-4-7