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The effects of molecular fluctuations on chemical oscillations and chaos are investigated. The calculations are carried out using a reactive lattice-gas automaton which provides a mesoscopic description of the reactive dynamics. A specific chemical model, the Willamowski–Rössler reaction, is used to illustrate the effects. The applicability of mass-action rate laws and reaction-diffusion equations are considered and the character of the fluctuations in various dynamical regimes for both spatially-distributed and spatially-homogeneous systems are examined. The work provides information on the molecular origin of macroscopic, self-organized structures in far-from-equilibrium reacting systems. [ABSTRACT FROM AUTHOR]

The onset of chemical turbulence in the 2-D complex Ginzburg–Landau equation is studied for a class of finite-amplitude, inhomogeneous, random initial conditions. Numerical simulations on a coupled map lattice corresponding to this reaction–diffusion equation are carried out in order to characterize the nature of the turbulent state. The phase diagram giving the zone of chemical turbulence in the parameter space that specifies the initial condition is determined numerically and compared with an analytical estimate. [ABSTRACT FROM AUTHOR]

The rate processes corresponding to barrier crossing dynamics in a symmetric double-well potential driven by a white-noise source are investigated. The rate kernels in the generalized phenomenological rate law describing the reaction involve time evolution through a projected Fokker–Planck operator. The spectral properties of the projected Fokker–Planck operator are studied, and the rate kernels are expressed in terms of the eigenvalues and eigenfunctions of this operator. The formal results are illustrated with numerical calculations. The results provide information on the nature of the generalized chemical rate law for fast processes. [ABSTRACT FROM AUTHOR]

Studies vortex core dynamics in the Brusselator both near to and far from the Hopf bifurcation line for random and pair initial conditions. Vortex dynamics near the oscillatory instability; Vortex dynamics in the relaxation oscillation domain.