Ruthenium-catalyzed Belousov-Zhabotinsky Reaction Research Articles

Quint points lattice in a driven Belousov-Zhabotinsky reaction model.

We report the discovery of a regular lattice of exceptional quint points in a periodically driven oscillator, namely, in the frequency-amplitude control parameter space of a photochemically periodically perturbed ruthenium-catalyzed Belousov-Zhabotinsky reaction model. Quint points are singular boundary points where five distinct stable oscillatory phases coalesce. While spikes of the activator show a smooth and continuous variation, the spikes of the inhibitor show an intricate but regular branching into a myriad of stable phases that have fivefold contact points. Such boundary points form a wide parameter lattice as a function of the frequency and amplitude of light absorption. These findings revise current knowledge about the topology of the control parameter space of a celebrated prototypical example of an oscillating chemical reaction.

Chirality observed in a driven ruthenium-catalyzed Belousov-Zhabotinsky reaction model.

Chirality is commonly associated with the spatial geometry of the atoms composing molecules, the biochemistry of living organisms, and spin properties. In sharp contrast, here we report chirality found in numerically computed stability diagrams of a chemical reaction governed by purely classical (that is, not quantum) equations, namely in a photochemically periodically perturbed ruthenium-catalyzed Belousov-Zhabotinsky reaction model. This novel chirality offers opportunities to explore hitherto unsuspected properties of purely classical chemical oscillators.

The effect of acetone on the dynamics of temporal oscillations and waves in the ruthenium-catalyzed Belousov-Zhabotinsky reaction.

The effect of acetone on temporal oscillations and spatio-temporal patterns occurring in the ruthenium-catalyzed Belousov-Zhabotinsky (BZ) reaction was investigated in a closed batch system. The periods of temporal oscillations and waves significantly decrease with increasing acetone concentration. At low concentrations of acetone (0.01-0.05 M), regular wave patterns are observed with prolonged lifetimes of both temporal oscillations and waves. However, for higher concentrations (0.10-1.00 M acetone), the lifetime is shortened and irregular patterns are formed. The photosensitivity of waves of the Ru(bpy)3(2+)-catalyzed BZ reaction remains the same for all acetone concentrations. The results are discussed in terms of the proposed reaction mechanism.

Response of a chemical wave to local pulse irradiation in the ruthenium-catalyzed Belousov-Zhabotinsky reaction.

The photo-sensitive Belousov-Zhabotinsky (BZ) reaction system was investigated to understand the response of wave propagation to local pulse stimulation in an excitable field. When the chemical wave was irradiated with a bright pulse or a dark pulse, the speed of wave propagation decreased or increased. The timing of pulse irradiation that significantly affected the speed of chemical wave propagation was different with the bright and dark pulses. That is, there is a sensitive point in the chemical wave. The experimental results were qualitatively reproduced by a numerical calculation based on a three-variable Oregonator model that was modified for the photosensitive BZ reaction. These results suggest that the chemical wave is sensitive to the timing of pulse irradiation due to the rates of production of an activator and an inhibitor in the photochemical reaction.

Chemical Wave Propagation Preserved on an Inhibitory Field in the Ruthenium-Catalyzed Belousov–Zhabotinsky Reaction

The propagation of a chemical wave on an inhibitory field, which was wedged between two excitable fields, was investigated for the photosensitive Belousov-Zhabotinsky (BZ) reaction. With an increase in the width of the inhibitory field between the excitable fields (W), the chemical wave divided into two waves at W = Wα. The divided chemical waves then coalesced at W = Wβ with a decrease in W. Wα was larger than Wβ, i.e., hysteresis on the width of the inhibitory field was observed between the division and coalescence of the chemical wave. The experimental results were qualitatively reproduced by a numerical calculation based on a three-variable Oregonator model modified for the photosensitive BZ reaction. These results suggest that the chemical wave may be preserved on the inhibitory field due to an activator supplied from a chemical wave on the excitable field.

Photoexcited Chemical Wave in the Ruthenium-Catalyzed Belousov–Zhabotinsky Reaction

The excitation of the photosensitive Belousov-Zhabotinsky (BZ) reaction induced by light stimulation was systematically investigated. A stepwise increase in the light intensity induced the excitation, whereas a stepwise decrease did not induce the excitation. The threshold values for the excitation were found to be a function of the initial and final light intensities, time variation in light intensity, and the concentration of NaBrO(3). The experimental results were qualitatively reproduced by a theoretical calculation based on a three-variable Oregonator model modified for the photosensitive BZ reaction. These results suggest that although the steady light irradiation is known to inhibit oscillation and chemical waves in the BZ system under almost all conditions, the stepwise increase in the light irradiation leads to the rapid production of an activator, resulting in the photoexcitation.

Desensitization effects in the ruthenium-catalyzed Belousov-Zhabotinsky reaction

The influence of visible light on the velocities of spiral waves in the [Ru(bpy)](3)(2+) -catalyzed Belousov-Zhabotinsky (BZ) reaction is well documented. However, there are only few reports showing the effect of the way a change in the applied intensity is made, or on "desensitization" or "memory" type phenomena. In this paper, we present observations showing significant changes in spiral tip dynamics without varying the light intensity during the course of the experiments. We produce further evidence showing that changes in wave velocity and inhibitory effects are depending on whether the increase in intensity is applied in one large step or in a number of smaller steps. Also, the tip trajectories before and after the spiral waves have been subjected to an increase and subsequent decrease in intensity levels are different, suggesting a change in excitation of the system. The experimental results are separated into two groups depending on the light sensitivity of the system and the behavior of the spiral tip. Simulation results demonstrate that the different tip trajectories observed in the experiments can be modeled by only varying the excitation threshold. Our observations indicate that there must be at least two different competing pathways for the reaction mechanism not only in the oscillatory BZ system but also in excitable media and that intermediates may also play an important part in determining the excitation of the system and not just the initial concentrations of the reactants.

Front propagation and mode-locking in an advection-reaction-diffusion system

Experiments are presented on chemical front propagation in an oscillating chain of vortices in which the mixing of passive impurities is chaotic. The excitable ruthenium-catalyzed Belousov-Zhabotinsky reaction is used in these studies. Velocities of the propagating fronts are measured as a function of the frequency and amplitude of external forcing. Mode locking is observed where the front propagates an integer number of vortices in an integer number of drive periods. Arnol'd tongues are mapped out for two of the locking regimes. These two tongues are shown to form a region of overlap where the velocity of the propagating front switches erratically between two locked values. The experimental results agree with numerical predictions of mode locking in a simplified model of the flow.

Sensing the distance to a source of periodic oscillations in a nonlinear chemical medium with the output information coded in frequency of excitation pulses

A spatially distributed excitable chemical medium can collect and process information coded in the propagating pulses of excitation. We consider the problem of distance sensing with the use of a nonlinear chemical medium. We demonstrate that a sensor that can feel the distance separating it from a source of periodic excitations can be constructed by a proper geometrical arrangement of excitable and nonexcitable regions. The sensor returns information about the distance in the frequency of outgoing pulses. The sensor functionality is tested by simulations based on the Rovinsky-Zhabotinsky model. The results are confirmed in experiments performed for a ruthenium-catalyzed Belousov-Zhabotinsky reaction.

Photo-induced excitations in the ruthenium-catalyzed Belousov–Zhabotinsky reaction

Photo-induced excitations in the tris-(bipyridyl)Ru(II)-catalyzed Belousov–Zhabotinsky reaction are studied numerically using the Oregonator model, modified to describe photosensitivity. An abrupt change in bromide concentration induced by a pulse-light perturbation causes a large excursion. The mimimal light intensity for initiating an excitation decreases while the system approaches to a bifurcation point. This study provides an alternative explanation for a recent experimental research.

Influence of Light on the Inorganic Part of the Ruthenium-Catalyzed Belousov-Zhabotinsky Reaction

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTInfluence of Light on the Inorganic Part of the Ruthenium-Catalyzed Belousov-Zhabotinsky ReactionM. K. Ram Reddy, Z. Szlavik, Zs. Nagy-Ungvarai, and S. C. MullerCite this: J. Phys. Chem. 1995, 99, 41, 15081–15085Publication Date (Print):October 1, 1995Publication History Published online1 May 2002Published inissue 1 October 1995https://doi.org/10.1021/j100041a025RIGHTS & PERMISSIONSArticle Views218Altmetric-Citations32LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (1 MB) Get e-Alerts

Effect of Visible Light on Wave Propagation in the Ruthenium-Catalyzed Belousov-Zhabotinsky Reaction

Effect of Visible Light on Wave Propagation in the Ruthenium-Catalyzed Belousov-Zhabotinsky Reaction

MULTI-ARMED SPIRALS IN A LIGHT-CONTROLLED EXCITABLE REACTION

The dynamics and geometry of multi-armed spirals in the light-sensitive ruthenium-catalyzed Belousov-Zhabotinsky reaction were investigated experimentally. The patterns were generated by a novel technique based on laser illumination, which allows the formation, control and annihilation of spiral waves. The rotation of n-armed spirals (n≤6) is stabilized by an unexcitable disk, created by a green laser beam. After switching off the laser, the central disk region becomes excitable again and individual cores are formed for each spiral arm. A symmetric collision structure appears periodically in the central region. Spiral arms are not attached to specific cores, but continuously passed on to the adjacent one. The geometry of multi-armed spirals is analyzed in polar coordinates and single arms are compared with a simple Archimedian shape.

Chemical spiral rotation is controlled by light-induced artificial cores

Dynamic features of spiral-shaped excitation waves rotating around unexcitable disks are investigated experimentally. The spiral patterns are observed in the ruthenium-catalyzed Belousov-Zhabotinsky reaction (bromination of malonic acid), in which the excitability depends on the intensity of applied illumination. Measurements are performed with a novel technique, which uses an argon laser beam for manipulation of wave propagation and creation of unexcitable disks, serving as artificial spiral cores. Rotation period, wavelength and velocity of spirals increase monotonically when the core radius is enlarged by expanding the diameter of the laser beam (0.1–3.0 mm). Rapid change of the core size is followed by a continuous relaxation process into a new dynamic state. The transient wavelengths and velocities scanned during this process provide data for a fast calculation of the dispersion relation for the investigated medium.

Phototaxis of Spiral Waves

The drift of spiral waves toward regions of higher light intensity was observed experimentally in the ruthenium-catalyzed Belousov-Zhabotinsky reaction. A light gradient can thus be used to manipulate optical information in new computational systems based on photochemical media. The drift of a gradient that is rotationally invariant in space is three to four times as fast as that of a translationally invariant gradient. Simulations based on the use of a cellular automaton, which is made isotropic by a semirandom distribution of cells, are in agreement with the experimental results.