MULTIPLICITY AND OSCILLATIONS IN A MODEL FOR CATALYZED OXIDATION OF CARBON-MONOXIDE

We extend a model proposed for explaining multiplicity and oscillation s of concentrations and temperature in catalyzed oxidation of carbon m onoxide; the importance of the dimension of the system and the closure approximation applied to the results, and, especially to the oscillat ory behavior, is analyzed. Kinetic phase transitions, namely, single s tate<-- --> multiplicity, single state<-- --> oscillations, and multip licity<-- --> oscillations are found, depending on the reaction heat a nd the temperature relaxation parameter. Also, the role played by deso rption of reactants is considered. When there is no desorption, temper ature oscillations take place around room temperature, but if desorpti on is operative, oscillations occur about a higher temperature. For th e one-dimensional case a spurious kinetic phase transition is obtained when the singlet closure approximation is applied.