Spontaneous Temporal and Spatial Phenomena in Physicochemical Systems

Abstract

From the very beginning chemists dealing with oscillations have been concerned with the question whether or not heterogeneity is a necessary prerequisite for the occurrence of oscillatory behaviour. Looking more closely into such systems, we can distinguish clearly two kinds of spatial structures:

• Permanent structures forming interfaces between different kinds of phases. The intirfaces, as a rule, are the sites of the oscillatory processes, as is the case at electrodes, heterogeneous catalysts, membranes, biological tissues etc..

• Dynamic structures arising from unstable situations which are present necessarily in all chemical and physicochemical oscillators. They manifest themselves in the form of propagating conversions of state or as dissipative structures. They may occur in all kinds of systems containing unstable states, either in the form of spatial or interfacial dynamic structures, the varying circumstances of which are illustrated in more detail in Fig. 1 and 2.