CROSS-SECTION OF LIGHT-INDUCED INHIBITION AND INDUCTION OF CHEMICAL OSCILLATIONS

The cross section is defined for light-induced inhibition and induction of chemical oscillations. The definition is based on the cross section of photochemical production of the key molecule which controls chemical oscillations and is shown to be useful in describing photosensitivity quantitatively. The cross section can be determined experimentally by measuring the critical light power for stoPPing or starting the oscillation. A unified treatment is given for the irradiation of a continuous-flow stirred tank reactor (CSTR) as well as for the preirradiation experiment, in which one of the chemical species is selectively irradiated in a prereactor in the flow experiment. A relation is given by which these two kinds of experiments can be correlated. The general procedure developed here is shown to be useful in analyzing thc wavelength-dependent irradiation experiments to identify the primary photochemical step and also in designing an appropriate flow reactor. Examples of its application to typical chemical oscillators are discussed.