The effect of an electric field on the local stoichiometry of front waves in an ionic chemical system

A model based on an autocatalytic, two-step reaction mechanism including tw o ionic components (of the same charge) and two non-ionic components, where both reactions are of second order overall, is considered when an electric held is applied to the system. The model is motivated by experimental obse rvations on the iodate-arsenous acid system. The travelling wave equations are examined first and conditions obtained for the existence and form of th ese waves. These conditions are then used to interpret the results obtained from numerical simulations of the full system. These results display all t he main features observed experimentally, the change in the local stoichiom etry and the possible wave annihilation for sufficiently strong fields. The model provides a clear explanation for these features as well as predictin g new features not reported from the experiments. The main one of which is the occurrence of an internal wave propagating in the reacted part of the s ystem in the direction induced by the applied field.