Reaction kinetics in confined geometries: lonely adatoms in space.

There is a close relation between the problems of second-layer nucleation in epitaxial crystal growth and chemical surface reactions, such as hydrogen recombination, on interstellar dust grains. In both cases, standard rate equation analysis has been found to fail because the process takes place in a confined geometry, and under typical conditions the mean number of reactant particles on the surface is small compared to unity (the lonely adatom regime). Using scaling arguments developed in the context of second-layer nucleation, I present a simple derivation of the hydrogen recombination rate for small and large grains. I clarify the reasons for the failure of rate equations for small grains, and point out a logarithmic correction to the reaction rate when the reaction is limited by the desorption of hydrogen atoms (the second-order reaction regime).

• Publication year

  2003

• Venue

  Physical review. E, Statistical, nonlinear, and soft matter physics

• Publication date

  2003-02-14

• Fields of study

  Materials Science, Physics, Medicine

• Identifiers
  DOI 10.1103/PhysRevE.67.065102arXiv cond-mat/0302307PMID 16241287
• External record

  Open on Semantic Scholar

• Source metadata

  Semantic Scholar, PubMed

• No claims are published for this paper.

• No concepts are published for this paper.

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