NONLINEAR PHENOMENA IN ELECTROCHEMICAL SYSTEMS

Many electrochemical systems are known to exhibit complex non-linear b ehaviour such as spontaneous oscillations of current or potential, com plex and chaotic oscillations and associated bifurcation scenarios and spatial pattern formation when maintained far from thermodynamic equi librium. We discuss the origin of electrochemical oscillations and arg ue that most of the currently known electrochemical oscillators belong to one of two different classes. These classes are distinguished by t he different types of electrical control under which oscillations are observable and are characterized by qualitatively different impedance spectra. The possibility of observing electrochemical oscillations und er truly potentiostatic conditions is discussed briefly, as well as th e role of global coupling, due to the electroneutrality condition in t he formation of spatiotemporal patterns on the electrode surface.