NEW RESULTS ON LIGHT-INDUCED SPATIAL BIFURCATION AND ELECTRICAL-FIELD EFFECT ON CHEMICAL WAVES IN THE HGCL2-KI SYSTEM IN GEL MEDIA

Novel experiments on one-dimensional propagation of a single red/yellow band of mercuric iodide in gel media have been carried out. At low pH values of mercuric chloride solution containing agar-agar, a single yellow band propagates downward in complete darkness. However, it bifurcates into a number of colorful alternate red and yellow bands in the presence of natural light. The influence of gravity and electrical field effect on the wave propagation at various field intensities, electrolyte concentrations, and tube diameters have been studied. The dependence of band location (d) on time (t) at various experimental conditions obeys the relation d2 = kt + C, where k and C are the slope and intercept, respectively. At low ]KI[ the red band bifurcates into several revert spaced bands at low field intensity in the presence of natural light. A critical field intensity exists at 0.016 V cm-1 beyond which a single red wave propagates.