Oscillatory reaction concentration waves

These models consider the mechanisms of formation of oscillations a mechanism involving the phase transition of planes Pt(100) (hex) (lxl) and a mechanism with the formation of surface oxides Pd(l 10). The models demonstrate the oscillations of the rate of C02 formation and the concentrations of adsorbed reactants. These oscillations are accompanied by various wave processes on the lattice that models single crystalline surfaces. The effects of the size of the model lattice and the intensity of COads diffusion on the synchronization and the form of oscillations and surface waves are studied. It was shown that it is possible to obtain a wide spectrum of chemical waves (cellular and turbulent structures and spiral and ellipsoid waves) using the lattice models developed [283], Also, the influence of the internal parameters on the shapes of surface concentration waves obtained in simulations under the limited surface diffusion intensity conditions has been studied [284], The hysteresis in oscillatory behavior has been found under step-by-step variation of oxygen partial pressure. Two different oscillatory regimes could exist at one and the same parameters of the reaction. The parameters of oscillations (amplitude, period, and the... 

The spiral or concentric waves observed for the spatial distribution of cAMP (fig. 5.6) present a striking analogy with similar wavelike phenomena found in oscillatory chemical systems, of which the Belousov-Zhabotinsky reaction (fig. 5.7) provides the best-known example (Winfree, 1972a). 

Chemical wave patterns corresponding to moving surface concentration patches are the result of coupling of siuface diffusion, surface reconstruction, and surface reaction. Depending on the reaction condition, such spatio-temporal phenomena can also lead to an oscillatory behavior of... 

Eager, M. D. Santos, M. Dolnik, M. Zhabotinsky, A. M. Kustin, K. Epstein, I. R. 1994. Dependence of Wave Speed on Acidity and Initial Bromate Concentration in the Belousov-Zhabotinsky Reaction-Diffusion System, J. Phys. Chem. 98, 10750-10755. Edblom, E. C. Luo, Y. Orban, M. Kustin, K. Epstein, I. R. 1989. Kinetics and Mechanism of the Oscillatory Bromate-Sulfite-Ferrocyanide Reaction, J. Phys. Chem. 93, 2722-2727. 

To calculate the critical perturbation necessary for wave initiation, we choose a modified Oregonator model [18-20] for an excitable and an oscillatory Belousov-Zhabotinsky reaction and numerically solve the deterministic reaction-diffusion equations for the system in one spatial dimension. We determine both the critical radius and the critical concentration change necessary for trigger wave propagation to proceed. We review the model in this section before proceeding to the results of the critical perturbations necessary for wave initiation. 

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