OXYGEN INFLUENCE ON COMPLEX OSCILLATIONS IN A CLOSED BELOUSOV-ZHABOTINSKY REACTION

The influence of oxygen on the cerium-catalyzed Belousov-Zhabotinsky r eaction is investigated in a system that is closed except for transpor t of oxygen from the atmosphere across a free surface. Experiments sho w that the introduction of oxygen increases the complexity of oscillat ions and shortens their duration. We determine the dependence of the o scillatory pattern on the concentration of oxygen in the reaction mixt ure, as measured with an oxygen electrode and controlled through the c ontent of oxygen above the free surface. We show that the influence of the stirring rate under aerobic conditions is mainly an oxygen effect and report oscillations of the oxygen concentration. Calculations bas ed on a modified Oregonator model show that the influence of oxygen ca n be qualitatively accounted for through the effect of two rate consta nts.