Controlled Excitations of the Belousov-Zhabotinsky Reaction: Experimental Procedures

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• 作者：Catalina Peralta ; Claudia Frank ; Alex Zaharakis ; Carolyn Cammalleri ; Matthew Testa ; Stephen Chaterpaul ; Christian Hilaire ; Daniel Lang ; Daniel Ravinovitch ; Sabrina G. Sobel ; Harold M. Hastings
• 刊名：Journal of Physical Chemistry A
• 出版年：2006
• 出版时间：November 9, 2006
• 年：2006
• 卷：110
• 期：44
• 页码：12145 - 12149
• 全文大小：63K
• 年卷期：v.110,no.44(November 9, 2006)
• ISSN：1520-5215

文摘

The purpose of this research was to explore the unstirred, ferroin-catalyzed Belousov-Zhabotinsky (BZ)reaction as an experimental model for the response of excitable media to small perturbations (slightly largerthan the threshold for excitations). Following Showalter et al. (Showalter, K.; Noyes, R. M.; Turner, H. J.Am. Chem. Soc. 1979, 101, 7463-69), we used a positively biased silver electrode to release silver ions intoa BZ reaction mixture, removing bromide ions and causing an excitation if sufficient bromide was removed.We found (1) a scaling region in which the delay before activation increased linearly as the size of theperturbation decreased, qualitatively consistent with but not fully explained by the Oregonator of Field et al.(Field, R. J.; Körõs, E.; Noyes, R. M. J. Am. Chem. Soc. 1972, 94, 8649-64); (2) evidence for a 10 soligomerization time scale; and (3) that activations were always delayed until after the end of a pulse ofcurrent, with the delay essentially constant for sufficiently long pulses, an effect not seen in simple ODEmodels but consistent with the anomalously large current apparently required for activation (Showalter, K.;Noyes, R. M. J. Am. Chem. Soc. 1976, 98, 3730-31) and explainable by bromide transport. Overall, the BZsystem appeared to be well-suited as an experimental prototype, despite its complexity.