Thumbnail
Access Restriction
Open

Author Suchorski, Yu. ♦ Beben, J. ♦ Imbihl, R. ♦ James, E. W. ♦ Liu, Da-Jiang ♦ Evans, J. W.
Sponsorship (US)
Source United States Department of Energy Office of Scientific and Technical Information
Content type Text
Publisher The American Physical Society
Language English
Subject Keyword CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS ♦ AMPLITUDES ♦ BIFURCATION ♦ CUSPED GEOMETRIES ♦ DIFFUSION ♦ ELECTRON MICROSCOPY ♦ FLUCTUATIONS ♦ FOCUSING ♦ KINETICS ♦ OXIDATION ♦ OXYGEN ♦ SUPERLATTICES
Abstract Local fluctuations and fluctuation-induced transitions in catalytic CO oxidation are studied with field electron microscopy on the (112) facets of a [100]-oriented Pt field emitter tip. The reaction is investigated in the bistable range close to the cusp point (critical point) that terminates the bistability range in p{sub CO}, T-parameter space. The amplitude and the spatial coherence of the fluctuations increase on approaching the critical point. The fluctuations are spatially well correlated on each flat (112) facet, but their correlation decays rapidly across stepped regions that terminate the flat facets. On smaller (112) facets, an onset of fluctuation-induced transitions is observed earlier (i.e., further away from the critical point) than for larger (112) facets. The behavior of the reaction system near the cusp point appears to be similar to that of an equilibrium system near the critical point. The observed fluctuations are mimicked in a simple reaction model for CO oxidation on surfaces that incorporates both rapid diffusion of adsorbed CO, and superlattice ordering of adsorbed immobile oxygen. The steady states of the model exhibit a cusp bifurcation, from a regime of bistability to one of monostability. The fluctuations increase near this cusp point, as in experiment. This behavior is analyzed via kinetic Monte Carlo simulations and analytic procedures, focusing on the consequences for fluctuation-induced transitions.
ISSN 01631829
Educational Use Research
Learning Resource Type Article
Publisher Date 2001-04-15
Publisher Place United States
Journal Physical Review B
Volume Number 63
Issue Number 16


Open content in new tab

   Open content in new tab