Electrochemical Monitoring of Photolytic Intermediates
1.
2.
3.
4.
5.
6. This is done so that the overall photochemical reaction hapens at steady state approximately.
7.
8.
9. Absorption by the photo active solute creates a high initial concentration of the primary intermediate, its decay with time often leads to the rise and fall of other transient species that appear later in the reaction scheme.
10. Because these time dependencies tell much about the photolysis mechanism flash methods are immensely valuable to photochemistry and have become very common.
11.
12.
13. The current decay is not linked simply to a time dependent bulk concentration of the electroactive substance. Superimposed on that time function is the normal cottrell decay from the diffusion process.
14.
15.
16. At time τ the switch closes, electrolysis begins and for a period thereafter one see a current decay that is governed by a corttell relation unperturbed by reactant disappeareance caused by decay.
17. An observation proportional to the bulk concentration of the transient species can be obtained by sampling the current at a fixed interval following τ.
18. Repeating the experiment with different potentials or different τ values enables one to derive current – potential curves for a sequence of delay times, hence we can obtain both qualitative and quantitative information about the transients.