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Adsorption

, Volume 6, Issue 3, pp 241–249 | Cite as

A Grand Canonical Monte-Carlo Simulation Study of Xenon Adsorption in a Vycor-like Porous Matrix

  • R.J.-M. Pellenq
  • S. Rodts
  • V. Pasquier
  • A. Delville
  • P. Levitz
Article

Abstract

We have performed atomistic Grand Canonical Monte-Carlo (GCMC) simulations of adsorption of xenon in a Vycor-like matrix at 195 K. The disordered mesoporous network is obtained by applying a numerical 3D off-lattice reconstruction procedure to a simulation box originally containing silicon and oxygen atoms of a non-porous silica solid. In order to reduce the computational cost, we have applied a homothetic decrease of the simulation box dimensions which preserves the morphology and the topology of the pore network (the average pore dimension is then around 30 Å). The surface chemistry is obtained in a realistic fashion by saturating all dangling bonds with hydrogen atoms. Small angle scattering spectra calculated on different numerical samples have evidenced a departure from Porod's law due to surface roughness. The simulated isotherms calculated on such disordered connected porous networks, show the capillary condensation phenomenon. The shape of the adsorption curves differs from that obtained for simple pore geometries. The analysis of the adsorbed quantity distribution indicates partial molecular-film formation depending on the local surface curvature and roughness.

silical glasses CPG Vycor adsorption capillary condensation molecular simulation Monte-Carlo SANS SAXS fractals surface roughness Porod's law Gurvitch rule hysteresis loop 

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Copyright information

© Kluwer Academic Publishers 2000

Authors and Affiliations

  • R.J.-M. Pellenq
    • 1
  • S. Rodts
    • 2
  • V. Pasquier
    • 2
  • A. Delville
    • 2
  • P. Levitz
    • 2
  1. 1.Centre de Recherche sur la Matière DiviséeCNRS et Université d'OrléansOrléans, cedex 02France
  2. 2.Centre de Recherche sur la Matière DiviséeCNRS et Université d'OrléansOrléans, cedex 02France

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