Abstract
The oscillation frequency of a nonlinear reaction system acts as a key factor for interaction and superposition of spatiotemporal patterns. To control and design spatiotemporal patterns in oscillatory media, it is important to establish the dominant frequency-related mechanism and the effects of external forces and species concentrations on oscillatory frequency. In the Ru(bipy)3(2+)-catalyzed Belousov-Zhabotinsky oscillator, a nonmonotonic relationship exists between light intensity and oscillatory frequency (I-F relationship), which is composed of fast photopromotion and slow photoinhibition regions in the oscillation frequency curve. In this work, we identify the essential mechanistic step of the I-F relationship: the previously proposed photoreaction Ru(II)* + Ru(II) + BrO3(-) + 3H(+) → HBrO2 + 2Ru(III) + H2O, which has both effects of frequency-shortening and frequency-lengthening. The concentrations of species can shift the light intensity that produces the maximum frequency, which we simulate and explain with a mechanistic model. This result will benefit studies of pattern formation and biomimetic movement of oscillating polymer gels.
The oscillation frequency is an important factor for pattern structuring and wave interaction in nature. However, for specific oscillatory chemical reactions, e.g., the classical photosensitive Belousov-Zhabotinsky reaction, there has been no detailed investigation of the oscillation frequency and the factors that influence it. In this work, we establish the essential mechanistic step for the nonmonotonic relationship between photointensity and oscillator frequency (I-F) in the photosensitive Belousov-Zhabotinsky system. We also show that species concentrations can shift the maximum of the I-F curve. This result will have wide applications for designing spatiotemporal patterns and controlling the shape and movement of active matter.