Alteration of Chemical Concentrations through Discreteness-Induced Transitions in Small Autocatalytic Systems

We study an autocatalytic system consisting of several interacting chemical species. We observe a strong dependence of the concentrations of the chemicals on the size of the system. This dependence is caused by the discrete nature of the molecular concentrations. Two basic mechanisms responsible for them are identified and elucidated. The relevance of the transitions to processes in biochemical systems and in micro-reactors is briefly discussed.