Irving Epstein and Anatol Zhabotinsky of Brandeis University are supported by the Experimental Physical Chemistry Program to carry out experimental and computational research in nonlinear chemical dynamics, focusing on creating and understanding a variety of new phenomena involving different aspects of pattern formation in reaction-diffusion systems. Four areas will be explored. First, the behavior of oscillating chemical reactions in water-oil-surfactant microemulsions will be examined, utilizing a new flow reactor configuration and a wider range of reactions and surfactants. Next, external light source perturbation will be used to probe Turing patterns, standing waves, and cluster patterns in the chlorine dioxide- iodine-malonic acid reaction, to seek new forms of resonant behavior and to study the facts of growth on pattern formation. As well, efforts will be undertaken to develop a systematic understanding of "chemical optics," the behavior of various types of chemical waves involving reflection, refraction, diffraction, and interference. Finally, new systems for pattern formation studies will be developed, including (a) oscillators involving calcium ions, (b) pH oscillators that oscillate in closed as well as open systems, (c) simple enzyme-based oscillators, and (4) the platinum-catalyzed reaction of hypophosphite ion with certain manganese species. Research outcomes will have potential applications to biology, catalysis, and information processing. As well, these phenomena are aesthetically appealing, and demonstrations and presentations can interest a wide range of scientific and lay audiences.
Pattern formation in chemistry is a central problem in modern macroscopic chemical kinetics. Reaction-diffusion systems constitute the most convenient analog models for pattern formation in neurobiology, catalysis, and ecology, and are useful for information processing. These phenomena involve global feedback and/or the propagation of chemical waves through nonuniform media.
