Study of the Extinction Dynamics of the Mercury Beating Heart Reaction in Acid Solution and in the Presence of γ-Radiation

Abstract

The dynamics of the oscillatory mercury beating heart (MBH) reaction in acid aqueous solution with Ce IV as the oxidizing agent was investigated. The reaction slowly runs down over a period of a few hours, until all oscillatory activity eventually ceases. During this period the dynamics slowly evolves, showing qualitatively different forms of oscillations. These oscillations display different modes of oscillations with geometric structures similar to heart, circle, pentagon, hexagon, and 8-and 16-pointed stars. As time proceeds, limitcycle oscillations of period-1, period-3, and period-2 appear successively. However, these oscillations are damped and could be interpreted in terms of a subcritical Hopf bifurcation. We propose different oxidationreduction reactions to explain the appearance of these cycles based on the formation of mercury(I) species, in the form of free Hg 2 2+ ion or, in molecular form, as a soluble mercurous sulfate or a mercurous sulfate film. The theoretical potential values calculated for these reactions agree well with our experimental values. An experiment was performed also without adding the Ce IV oxidant, generating in situ species of Hg(I) by γ-irradiating the metallic Hg in the same acid solution as before. It is shown that 60 Co γ-rays induce the generation of oscillations. In this way we support our claim that oscillations are due to the formation of chemical species of Hg(I) be it ionic or molecular and that extinction occurs when [Hg(II)] . [Hg(I)].

Self-Powered Gallium-Based Liquid-Metal Beating Heart

“…They deduced that the reason of oscillation was attributed to the change of surface tension caused by charge density difference. Castillo-Rojas et al 3 found that the mercury drop in aqueous solution with Ce IV could demonstrate different oscillation modes, such as circle, pentagon, hexagon, and 8-and 16pointed stars, resulting from a dynamic voltage produced in the chemical reaction. When an external power was supplied, Olson et al 4 showed that the oscillation mode could be sustained and altered from breather to 2-, 3-and 4-fold.…”

Asymmetry induced suppression of chaos

“…The signals (electrode potentials) are recorded between the Pt wires and Fe nails using the data acquisition control card (DAQ measurement computing USB-1616HS-4, 1000 Hz) with a computer interface. The details of the underlying nonlinear dynamics and chemistry of the regular and chaotic MBH oscillator can be found in the relevant literature [26][27][28][29][30][31][32][33] . Specifically, we consider the MBH oscillators in the parameter range that has been shown to yield chaotic dynamics 32 .…”

Extensive Study of Shape and Surface Structure Formation in the Mercury Beating Heart System

“…According to Keizer et al, 2,3 surface tension changes result from the formation and removal of a mercury sulfate film on the mercury surface in acid solution. The most complete chemical mechanism was proposed by Castillo-Rojas et al; 9 in their work they study the MBH system in acid solution with Pt as WE, iron as CE, and saturated calomel electrode as RE. Their proposed mechanisms consider different oxidizing agents for Hg 0 depending to their oxidizing strength.…”

“…The most complete chemical mechanism was proposed by Castillo-Rojas et al. ; in their work they study the MBH system in acid solution with Pt as WE, iron as CE, and saturated calomel electrode as RE. Their proposed mechanisms consider different oxidizing agents for Hg 0 depending to their oxidizing strength.…”