Non-equilibrium behaviour in isothermal liquid chemical systems

Abstract

This paper reviews the main features, goals, and achievements of a field of research that is now commonly referred to as ‘Chemical Dynamics’. This is neither ‘Molecular Dynamics’, nor ‘Chemical Kinetics’, in the traditional sense, but rather, the study of the universal properties of time evolution and/or spatial structure of chemical systems evolving far from equilibrium. This field has emerged over the last fifteen years. It has produced a great variety of new insights on the capability of chemical systems to organize spontaneously. It constitutes the contribution of Chemistry to the general interest that developed in practically all fields to address the question of creation of patterns and their evolution. As indicated by the title, we shall only consider examples of liquid systems, at fixed temperature, and in homogeneous conditions. Therefore, we leave out other types of systems that may give rise to similar or related behaviours, like gas reactions, combustions, electrochemical and heterogeneous systems, or any chemical engineering processes. In fact, most of the results, definitions as well as general behaviours, can be transposed to these systems. This points out the universality of the approach. A general overview of the field is given first and may be considered as a short version of the paper. Next, two sections are devoted to a more refined and formalized approach to temporal and spatio-temporal phenomena respectively. In both sections, experimental as well as theoretical tools are presented. Topology being an important aspect of these phenomena, we present many more pictures than equations. The article concludes with a chemical recipe that everyone should try.