PHOTOINDUCED PH OSCILLATIONS IN THE HYDROGEN PEROXIDE-SULFITE-FERROCYANIDE SYSTEM IN THE PRESENCE OF BROMOCRESOL PURPLE IN A CONTINUOUS-FLOW STIRRED-TANK REACTOR

The H2O2 - SO32- - Fe(CN)(6)(4-) system, one of the pH oscillators, is shown to be sensitive to visible light. Addition of a pH indicator, b romocresol purple (BCP), to this system is found to acquire new nonlin ear interactions due to the screening effect of the indicator. The osc illatory region in a state diagram spanned by the flow rate and the ir radiation light power shifts and becomes broader by the addition of in dicator. This behavior is also confirmed by a simulation calculation. Because of extremely high extinction of light at 590 nm due to the ind icator, it is expected that the system can be used for experiments on wave propagation and spatial patterns in thin films.