PHOTOINDUCED BIFURCATION AND MULTISTABILITY IN THE OSCILLATORY BRIGGS-RAUSCHER REACTION

The effect of continuous light irradiation on the Briggs-Rauscher syst em has been investigated by the light intensity scanning method. A sta te diagram has been established in the control parameter plane spanned by the initial concentration of I- ([I-](0)) and the light power (P). An increase of [I-](0) leads to a transition from the large-amplitude oscillatory state (OS) to the reduced steady state (SSI), whereas an increase of P gives rise to a transition from OS to the oxidized stead y state (SSI). Both transitions are accompanied by hysteresis, resulti ng in tristability among OS, SSI, and SSII in the overlapped part of t he two hysteresis regions. In addition to the photoinhibition reported previously, the photoinduction of oscillations has been found in a ce rtain range of [I-](0). In the low-[I-](0) region, bistability between OS and another oscillatory state with small amplitude (OS') has also been discovered. The origin of the transitions is discussed on the bas is of photoinduced autocatalytic processes.