Chemical turbulence and standing waves in a surface reaction model: The influence of global coupling and wave instabilities

Item Type:	Article
Title:	Chemical turbulence and standing waves in a surface reaction model: The influence of global coupling and wave instabilities
Creators Name:	Bär, M. and Hildebrand, M. and Eiswirth, M. and Falcke, M. and Engel, H. and Neufeld, M.
Abstract:	Among heterogeneously catalyzed chemical reactions, the CO oxidation on the Pt(110) surface under vacuum conditions offers probably the greatest wealth of spontaneous formation of spatial patterns. Spirals, fronts, and solitary pulses were detected at low surface temperatures (T<500 K), in line with the standard phenomenology of bistable, excitable, and oscillatory reaction-diffusion systems. At high temperatures (T greater, similar 540 K), more surprising features like chemical turbulence and standing waves appeared in the experiments. Herein, we study a realistic reaction-diffusion model of this system, with respect to the latter phenomena. In particular, we deal both with the influence of global coupling through the gas phase on the oscillatory reaction and the possibility of wave instabilities under excitable conditions. Gas-phase coupling is shown to either synchronize the oscillations or to yield turbulence and standing structures. The latter findings are closely related to clustering in networks of coupled oscillators and indicate a dominance of the global gas-phase coupling over local coupling via surface diffusion. In the excitable regime wave instabilities in one and two dimensions have been discovered. In one dimension, pulses become unstable due to a vanishing of the refractory zone. In two dimensions, turbulence can also emerge due to spiral breakup, which results from a violation of the dispersion relation.
Source:	Chaos
ISSN:	1054-1500
Volume:	4
Number:	3
Page Range:	499-508
Date:	September 1994
Official Publication:	https://doi.org/10.1063/1.166028
PubMed:	View item in PubMed

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