Kinetics of photoresponse of the chlorine dioxide-iodine-malonic acid reaction

We studied the photoresponse of the chlorine dioxide-iodine-malonic acid (C DIMA) reaction. In a continuously fed stirred tank reactor, the photosensit ivity increases with decreasing residence time and increasing concentration of chlorine dioxide. Under certain conditions, concentrations change in a sigmoidal fashion in response to a jump in the intensity of illumination. W e propose a new mechanism for the effect of visible light on the CDIMA reac tion. Simulations based on the proposed mechanism accurately describe the e xperimentally observed kinetics.