In this article we consider the CO oxidation on Ir(111) surfaces under large external noise with large autocorrelation imposed on the composition of the feed gas, both in experiments and in theory. We report new experimental results that show how the fluctuations force the reaction rate to jump between two well defined states. The statistics of the reaction rate depend on those of the external noise, and neither of them have a Gaussian distribution, and thus they cannot be modeled by white or colored noise. A continuous-time discrete-state Markov process is proposed as a suitable model for the observed phenomena. The model captures the main features of the observed fluctuations and can be modified to accommodate other surface reactions and other systems under non-Gaussian external noise.
Bibliographical noteFunding Information:
This work was supported by an International Cooperation Grant between Germany (Deutsche Forschungsgemeinschaft (DFG) Project WE4100/3) and Chile (Conicyt Project 079-2009): “Effects of large noise in the CO oxidation on Iridium(111) surfaces within the bistable regime.” O.D. and J.C. wish to thank the support of Fondecyt (Project 1110360).