Electrogenerated chemiluminescence in mechanistic investigation of electroorganic reactions: Part IV. Luminescence oscillations at the falling mercury drop

In the intensity-potential curves of the electrogenerated chemiluminescence at the dropping mercury electrode spikes are observed, which are due to the reaction of excessive anion radicals A^?. at the falling mercury drop. The luminescence trace of the drop exhibits a characteristic intensity pattern. These oscillations arise from an interplay of a concentration difference of A^?. between the front and back sides or the falling drop, which is hydrodynamically caused and leads to a corresponding difference in the electrochemical potential and in the surface tension, and a surface movement of the mercury as the retroactive effect. The influence of the experimental conditions and the structural effect of the investigated cathodic luminescence systems on the oscillating behavior are studied.