Year of Award

2012

Document Type

Dissertation

Degree Type

Doctor of Philosophy (PhD)

Degree Name

Chemistry

Department or School/College

Department of Chemistry and Biochemistry

Committee Chair

Richard J. Field

Commitee Members

Michael DeGrandpre, Donald Kiely, Robert Yokelson, Jesse Johnson

Keywords

anomalous dispersion, BZ reaction, chemical kinetics

Abstract

A modified six-variable Oregonator model presented here successfully reproduces a significant portion of the behavior observed in the Ferroin-catalyzed cyclohexanedione variant of the Belousov-Zhabotinsky (CHD-BZ) reaction. The phenomena of anomalous velocity dispersion (in which following waves may catch up to, rather than fall behind an initial excitation wave), wave-stacking, and backfiring have been successfully reproduced numerically as resulting from non-monotonic [Br-] decay to the steady state in the wake of an excitation pulse. The non-monotonic decay is seen as a "dip" in [Br-] following the passage of a chemical wave. This dip in [Br-] decay curve allows a following wave to accelerate and catch up to the initial wave. The origin of anomalous dispersion as the result of such a non-monotonic decay curve in [Br-] has been suggested previously by Steinbock et al. and Szalai et al. However, the work presented here is the first successful representation of anomalous wave-velocity dispersion using a chemical model. This model is based on the well-understood chemistry of the Oregonator model of the Belousov-Zhabotinsky reaction, coupled to a second pathway (based on chemistry related to uncatalyzed bromate oscillators) for the oxidation of organic substrate to provide the new dynamics.

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© Copyright 2012 Ryan Boger