Targets, ripples and spirals in a precipitation system with anomalous dispersion
| Autor: | Mahmoud M. Ayass, István Lagzi, Mazen Al-Ghoul |
|---|---|
| Rok vydání: | 2015 |
| Předmět: |
chemistry.chemical_classification
Mercury Compounds Chemistry Precipitation (chemistry) business.industry Iodide Potassium Iodide Temperature General Physics and Astronomy Iodides Breakup Pattern selection Molecular physics Instability Diffusion Wavelength Optics Mercuric iodide Physical and Theoretical Chemistry business Gels Phase diagram |
| Zdroj: | Physical Chemistry Chemical Physics. 17:19806-19814 |
| ISSN: | 1463-9084 1463-9076 |
| DOI: | 10.1039/c5cp01879j |
| Popis: | We present a novel reaction-diffusion system that exhibits three-dimensional superdiffusive traveling waves without utilizing any external forces. These waves include single circular targets, spirals, and ripples as well as phase-like waves. The system is based on the interplay of the precipitation reaction of mercuric iodide in a gel medium, its polymorphic transformation to a different crystalline form, and its redissolution in excess iodide. A phase diagram is constructed as a function of the initial concentrations of the reagents. The spatiotemporal evolution of these waves is thoroughly analyzed and seems to be a consequence of an anomalous dispersion relationship. Pattern selection and wavelengths of propagating waves are found to depend on initial concentrations of the reactants. The breakup of the waves is also investigated. While the breakdown of ripples and spirals is shown to be a consequence of a Doppler-like instability in conjunction with anomalous dispersion, the targets undergo a boundary defect-mediated breakup. |
| Databáze: | OpenAIRE |
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