A Model for the Surface Diffusion of Molecules on a Heterogeneous Surface

Sean P Rigby

Research output: Contribution to journalArticle

11 Citations (Scopus)

Abstract

A new model to explain the effects of the variation of temp. and surface coverage on the surface diffusion of mols. on heterogeneous surfaces has been presented. In this model, the emphasis is placed on understanding the influence of surface structure and geometry on the surface diffusion process. The model is a multifractal version of the so-called "homotattic patch" model that is often used in studies of gas adsorption on heterogeneous surfaces. Some previous exptl. results, reported in the literature, on the surface diffusion of benzene on a fumed silica, have been reanalyzed in the light of the new model. This reanal. of past data has suggested that, at a given value of overall av. surface coverage, the surface diffusion flux in this system is dominated by only a small fraction of the total no. of mols. on the surface. In addn., the small fraction of mols. that are the predominant contributors to the surface diffusion flux are generally adsorbed within particular regions of the surface. The particular regions contained within the different surface patches in the model were found to have differing degrees of surface roughness, which could be characterized by different surface fractal dimensions. This work has also shown that it may be possible to use surface diffusion methods to det. the characteristic size and spatial distribution of the different surface patches with different adsorption energies in homotattic patch models of heterogeneous adsorbent surfaces. [on SciFinder (R)]
Original languageEnglish
Pages (from-to)364-376
Number of pages13
JournalLangmuir
Volume19
Issue number2
Publication statusPublished - 2003

Fingerprint

Surface diffusion
surface diffusion
Molecules
molecules
Fluxes
Gas adsorption
adsorption
Fractal dimension
Benzene
Surface structure
Silicon Dioxide
Adsorbents
Spatial distribution
adsorbents
fractals
Surface roughness
spatial distribution
surface roughness
Silica
benzene

Keywords

  • surface diffusion of mol. on heterogeneous surface)
  • surface diffusion of mol. on heterogeneous surface studied using)
  • Diffusion (surface
  • simulation surface diffusion heterogeneous substrate
  • Adsorption enthalpy (surface diffusion of mol. on heterogeneous surface studied using)
  • Isotherms (adsorption

Cite this

A Model for the Surface Diffusion of Molecules on a Heterogeneous Surface. / Rigby, Sean P.

In: Langmuir, Vol. 19, No. 2, 2003, p. 364-376.

Research output: Contribution to journalArticle

Rigby, Sean P. / A Model for the Surface Diffusion of Molecules on a Heterogeneous Surface. In: Langmuir. 2003 ; Vol. 19, No. 2. pp. 364-376.
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