Stochastic model calculation for the carbon monoxide oxidation on iridium(111) surfaces

Jaime Cisternas*, Daniel Escaff, Orazio Descalzi, Stefan Wehner

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

9 Scopus citations


We study the effect of external noise on the catalytic oxidation of CO on an Iridium(111) single crystal under ultrahigh vacuum conditions. This reaction can be considered as a model of catalysis used in industry. In the absence of noise the reaction exhibits one or two stable stationary states, depending on control parameters such as temperature and partial pressures. When noise is added, for instance, by randomly varying the quality of the influx mixture, the system exhibits stochastic reaction rate and switching. In this work, we present two approaches: one for the monostable regime, and another for the bistable situation that relies on a white noise approximation. Both approaches rest on the assumption that spatial patterns of coverage on the Iridium plate can be neglected on a first approximation. Using mathematical models, it is possible to reconstruct stationary probability distribution functions that match experimental observations and provide support for the existence of a thermodynamic potential.

Original languageEnglish
Pages (from-to)3461-3472
Number of pages12
JournalInternational Journal of Bifurcation and Chaos in Applied Sciences and Engineering
Issue number10
StatePublished - Oct 2009

Bibliographical note

Funding Information:
J. Cisternas and O. Descalzi were supported by Fondecyt Grant 1070098. J. Cisternas, O. Descalzi and D. Escaff were supported by a Universidad de los Andes Grant (2009). D. Escaff was supported by postdoctoral Fondecyt Grant 3070013. S. Wehner’s visit to Santiago was supported by Fondecyt Grant 7070052. J. Cisternas is grateful to H. H. Roter-mund for sharing some of his latest experimental results, and to E. Tirapegui and M. Clerc for valuable comments.


  • Bistability
  • Noise
  • Stochastic differential equations
  • Surface reactions


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