Universality, multiplicity, and the effect of iron impurities in the Belousov–Zhabotinskii reaction

TLDR: In this article, a sequence of period doubling bifurcations was observed as a parameter was varied, and beyond the accumulation point for the period doubling sequence there was a sequence with the same symbolic dynamics as the states of the U (universal) sequence of Metropolis, Stein, and Stein (1973).

Abstract: In experiments on the Belousov–Zhabotinskii reaction in a flow reactor we have observed dynamical behavior that is described well by one‐dimensional maps with a single maximum. A sequence of period doubling bifurcations was observed as a parameter was varied, and beyond the accumulation point for the period doubling sequence there was a sequence of periodic states that has the same symbolic dynamics as the states of the U (universal) sequence of Metropolis, Stein, and Stein (1973). However, in another experiment with malonic acid from a different vendor, we found that some states with particular symbol sequences occurred in three different parameter ranges rather than in one range as in the U sequence. Analysis of the effect of impurities in the reagents showed that some impurities (e.g., Fe3+ and esters of malonic acid) at concentrations of only a few ppm produced dramatic changes in the dynamics; such impurities are contained in commercially available malonic acid. Experiments with purified malonic acid...