A quantitative study of chemical waves in the Belousov–Zhabotinsky reaction

Measurements are reported of velocities, amplitudes, and profiles in space and time of chemical waves in the Belousov–Zhabotinsky reaction at various temperatures, depths of solution, and initial reactant concentrations. The measurements are made in a thin layer of a quiescent, but excitable solution by means of light absorption by ferroin, the tris(1,10-phenanthroline) ferrous sulfate complex. Propagating wave profiles are recorded on a linear photodiode array (25.6 mm length) with a spatial resolution of 50 μ. The determinations of velocity corroborate previous experimental findings. New results include experimental verification of the constancy of the concentration profile of the wave in space and time; determination of two characteristic time constants in the relaxation of the wave profile; trends in wave amplitude with variation of initial reactant concentrations and age of the reaction mixture; wave velocity as a function of temperature, and solution depth; and measurements of wave annihilation. Observations of additional structure include the onset of mosaic structure, that is the transition from a homogeneous to an inhomogeneous state due to the passage of the wave, and initiation spikes.